10.5826/dpc.1303a170
Introduction: Nail diseases are often diagnosed late with a potential prognostic and functional im-pact. This could be partly due to knowledge gaps among primary care physicians (PCPs).
Objectives: To evaluate the knowledge about diagnosis and management of ten common/important nailconditions in a population of French PCPs and its improvement after a 31-minute online training session.
Methods: We submitted 10 pre-test and post-test clinical cases and an educative online course on the diagnosis and the management of nail diseases to 138 volunteer PCPs; 73 completed the whole training path.
Results: Compared to pre-test, more PCPs in the post-test required an urgent second opinion to der-matologist for pigmented melanoma (100% versus 80.3%; P &lt;0.05) and use of inappropriate/danger-ous systemic treatment for trauma-induced nail changes was reduced after the training program (0% versus 6.8%; P &lt;0.05).A lack of knowledge remained after training for amelanotic melanoma with an increase of mycological/bacteriological tests (9.6% versus 0%; P &lt;0.05).
Conclusions: Management of nail diseases by our panel of PCPs was suboptimal and was improved after a short online training.
text/xml
2160-9381
3064
en
Luc Thomas
https://creativecommons.org/licenses/by-nc/4.0
Dermatology Practical & Conceptual
melanoma
Evaluation of the Knowledge of Primary Care Physicians About Important Nail Diseases Before and After a Short Online Training
Text.Serial.Journal
https://dpcj.org/index.php/dpc
Original Article
2023-07-31
2022-12-12
2023-07-31
2023-08-24
e2023170
Dermatol Pract Concept
Introduction: Nail diseases are often diagnosed late with a potential prognostic and functional im-pact. This could be partly due to knowledge gaps among primary care physicians (PCPs).
Objectives: To evaluate the knowledge about diagnosis and management of ten common/important nailconditions in a population of French PCPs and its improvement after a 31-minute online training session.
Methods: We submitted 10 pre-test and post-test clinical cases and an educative online course on the diagnosis and the management of nail diseases to 138 volunteer PCPs; 73 completed the whole training path.
Results: Compared to pre-test, more PCPs in the post-test required an urgent second opinion to der-matologist for pigmented melanoma (100% versus 80.3%; P &lt;0.05) and use of inappropriate/danger-ous systemic treatment for trauma-induced nail changes was reduced after the training program (0% versus 6.8%; P &lt;0.05).A lack of knowledge remained after training for amelanotic melanoma with an increase of mycological/bacteriological tests (9.6% versus 0%; P &lt;0.05).
Conclusions: Management of nail diseases by our panel of PCPs was suboptimal and was improved after a short online training.
Luc Thomas
2023/07/31
10.5826/dpc.1303a170
e2023170
Dermatology department, Hôpital Lyon Sud, Hospices Civils de Lyon; Claude Bernard Lyon-1 University; Cancer Research Center of Lyon, Lyons, France
2160-9381
melanoma
en
e2023170
Summerbell RC, Cooper E, Bunn U, Jamieson F, Gupta AK. Onychomycosis: a critical study of techniques and criteria for confirming the etiologic significance of nondermatophytes. Med Mycol. 2005;43(1):39-59. DOI: 10.1080/13693780410001712043. PMID: 15712607.
Evaluation of the Knowledge of Primary Care Physicians About Important Nail Diseases Before and After a Short Online Training
https://dpcj.org/index.php/dpc/article/download/3064/2202
     Evaluation of the Knowledge of Primary Care
    Physicians About Important Nail Diseases Before
            and After a Short Online Training
         Pauline Greco1,2, Félix Pham1,2, Gérard Duru2, Xavier Lainé2, Stéphane Dalle1,2,3,
                                          Luc Thomas1,2,3


1 Dermatology department, Hôpital Lyon Sud, Hospices Civils de Lyon, Lyons, France
2 Claude Bernard Lyon-1 University, Lyon, France
3 Cancer Research Center of Lyon, Lyons, France



Key words: nail, primary care physician, education, general practitioner, melanoma
Citation: Greco P, Pham F, Duru G, Lainé X, Dalle S, Thomas L. Evaluation of the Knowledge of Primary Care Physicians About Important
Nail Diseases Before and After a Short Online Training. Dermatol Pract Concept. 2023;13(3):e2023170. DOI: https://doi.org/10.5826
/dpc.1303a170
Accepted: February 1, 2023; Published: July 2023
Copyright: ©2023 Greco et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-
NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use,
distribution, and reproduction in any medium, provided the original authors and source are credited.
Funding: This work was supported in part by grants from Lyon 1 Claude Bernard University (to LT), The Hospices civils de Lyon (to LT)
and the Association Vaincre le mélanome (to LT)
Competing Interests: None.
Authorship: All authors have contributed significantly to this publication.
Corresponding Author: Luc Thomas, MD, PhD, Service de dermatologie, Hôpital Lyon Sud, 165 Chemin du Grand Revoyet, 69310
Pierre-Bénite, France. Fax number: +33478865706 Email: luc.thomas@chu-lyon.fr
IRB Approval Status: Reviewed and approved by the institutional ethical committee of Lyons (N°20-63)




  ABSTRACT             Introduction: Nail diseases are often diagnosed late with a potential prognostic and functional im-
                       pact. This could be partly due to knowledge gaps among primary care physicians (PCPs).
                       Objectives: To evaluate the knowledge about diagnosis and management of ten common/important nail
                       conditions in a population of French PCPs and its improvement after a 31-minute online training session.
                       Methods: We submitted 10 pre-test and post-test clinical cases and an educative online course on
                       the diagnosis and the management of nail diseases to 138 volunteer PCPs; 73 completed the whole
                       training path.
                       Results: Compared to pre-test, more PCPs in the post-test required an urgent second opinion to der-
                       matologist for pigmented melanoma (100% versus 80.3%; P <0.05) and use of inappropriate/danger-
                       ous systemic treatment for trauma-induced nail changes was reduced after the training program (0%
                       versus 6.8%; P <0.05). A lack of knowledge remained after training for amelanotic melanoma with an
                       increase of mycological/bacteriological tests (9.6% versus 0%; P <0.05).
                       Conclusions: Management of nail diseases by our panel of PCPs was suboptimal and was improved
                       after a short online training.



Original Article | Dermatol Pract Concept. 2023;13(3):e2023170                                                                          1
Introduction                                                       2021. This study was approved by the Ethical Committee of
                                                                   the Université Claude Bernard Lyon 1 (Institutional Review
Nail disorders are very common but might not be very               Board N°2020-07-07-08, on July the 7th in 2020).
well-known by primary care physicians (PCPs). Although                We sent by e-mail a web link leading to our online ed-
50% of nail conditions are due to fungal infection, other dis-     ucative path to all PCPs members of the URPS union of
eases affecting the nail unit are neoplastic, inflammatory, con-   Auvergne/Rhone-Alpes region and Grand Est region hosted
genital, traumatic, or related to a systemic disease. Because      by Claroline®, the official educational website of Lyon
some of these non-fungal conditions clinically look alike on-      1 Claude Bernard University. It was first composed of a
ychomycoses, their diagnosis is often missed. Patients may be      10-clinical-case pre-test, followed by a 31-minute educative
then exposed to diagnostic delays with important prognostic        video (https://clarolineconnect.univ-lyon1.fr/resource/open/
significance especially in malignant tumors such as subungual      file/4776658 in French) and lastly a distinct 10-case post-test.
melanoma (SUM) or subungual squamous cell carcinoma                The link for the post-test was only available when the ap-
(SSCC) [1]. Moreover, they are often submitted to inappro-         plicant had validated the pre-test and completely watched
priate treatments. Many publications underline that diagnosis      the educative video. Pre- and post-test, for each case, in-
of SUM can be delayed from 9 months to 2.2 years after oc-         cluded a multiple-choice question with pre-determined an-
currence of the first symptoms [2,3]. These diagnostic delays      swers about management and a single choice question with
are responsible in part of the apparent worse prognosis of         pre-determined answer for the diagnostic orientation. Both
SUM yet, for an equivalent Breslow index, their prognosis is       pre- and post-test included distinct cases of one pigmented
not different from that observed in melanoma occurring else-       SUM, one amelanotic SUM, one SSCC, one trauma-induced
where on skin [4]. Confounding various nail conditions with        nail change, one onychomycosis, one nail unit psoriasis, one
fungal infection also led to an inappropriate use of medical       SGCT, one nail case of alopecia areata, one periungual viral
resources such as urgent dermatology consultations, imaging,       wart and one subungual hemorrhage. Management propos-
mycology tests and to unnecessary use of antifungal drugs.         als for each case were (one or more answer boxes could be
This is particularly true with repetitive trauma-induced toe-      ticked): “clinical follow-up”, “radiology imaging”, “myco-
nail changes due to the conflict between the shoe and the tip-     logical or bacteriological test”, “non-urgent dermatologist
toes. This condition not only looks like fungal infection but      second opinion”, “orthopedic surgeon second opinion”,
is also frequently contaminated with fungus, therefore identi-     “podiatrist consultation”, “topical antifungal”, “other topi-
fiable by laboratory tests [5]. In such cases, antifungal treat-   cal treatment”, “systemic treatment”, and “urgent dermatol-
ment may show some improvement that is rarely complete             ogist second opinion”. The diagnostic proposal for each case
and often followed by a relapse since the real cause of the nail   (only one answer box could be ticked) were the 10 conditions
change is underestimated. Moreover, subungual glomus-cell          listed above. During the teaching video, all these conditions
tumor (SGCT), a sometimes very painful benign tumor, is            were covered by vocal explanations and images of several
known to be frequently left untreated for as long as 1 to 9        examples and five simple rules to improve diagnostic strat-
years with significant risk of disability and depression [6,7].    egy in nail disease was taught : (1) thinking about nail tumor
                                                                   when a condition is monodactylic, (2) referring to derma-
Objectives                                                         tologist for brown or black but also red or white-yellowish
                                                                   longitudinal nail band, (3) spontaneous nail plate erosion is
The main objectives of our study were to evaluate the              not banal, (4) referring to dermatologist for non resolutive
potential lack of knowledge of PCPs about common or                and painful nail condition and (5) evaluate the static and the
prognostically/functionally important nail diseases, to pro-       dynamic of feet for toenail disease.
pose an online teaching session and to evaluate its improve-          The answers to the pre- and the post-test were
ment, particularly under the perspective of a better use of        pre-determined before the launch of the educative program
medical and therapeutic resources. Our secondary goal was          by a consensus of nail diseases experts and were classified
to evaluate pieces of knowledge where the improvements             as “compulsory” (+15 points), “correct” (0 points), “ac-
were the most significant and to identify topics in which our      ceptable” (-5 point), “inappropriate” (-10 points) or “dan-
teaching program could be improved.                                gerous” (-30 points). An example of “compulsory” answer
                                                                   was an urgent dermatologist second opinion for pigmented
Methods                                                            or amelanotic SUM or podiatrist consultation in case of
                                                                   trauma-induced nail change. An example of “dangerous an-
Study Design                                                       swer” was clinical follow-up for SSCC. For onychomycosis
We conducted a blinded anonymous study on 138 PCPs                 and psoriasis, no “dangerous” management were consid-
over a three-month period from November 2020 to January            ered. An example of “acceptable” answer was an orthopedic



2                                                                      Original Article | Dermatol Pract Concept. 2023;13(3):e2023170
surgeon second opinion for SUM, an example of “inappro-           pre-test scores of the participants who did not complete the
priate” answer was imaging for nail psoriasis. Although our       whole training path to the others did not show significant
study was more focused on the management of the cases,            difference.
diagnostic orientation was also evaluated during pre- and            When comparing pre and post-test, the number of com-
post-tests. A correct answer was given 5 points. Rating for all   pulsory and correct answers was significantly higher in the
answers was discussed with our biostatistician (GD).              post-test. For management, the correct answer (ie “clinical
    Some other common nail conditions were also briefly           follow up”) raised from 6/73 (8.2%) to 19/73 (26%) in
covered during the course (ingrown nail, pyogenic granu-          warts (P=0.002), from 16/73 (21.9%) to 33/73 (45.2%) in
loma, mucoid pseudocyst, ungual changes in systemic dis-          trauma-induced nail changes (P = 0.002; Table 1).
ease, onychotillomania and some benign nail tumors). All             A podiatrist consultation for trauma-induced nail
cases shown during the pre-test were included in the teaching     changes was proposed in only 13/73 (17.8%) of the pre-test
examples during the video course and expected answers to          but raised to 55/73 (75.3%) in the post-test (P < 0.001). For
the questionnaire were then disclosed for each. Indeed, none      pigmented SUM, 59/73 (80.3%) of PCPs required an urgent
of the cases used for the post-test were included in the video    dermatologist second opinion in the pre-test whereas all
as examples.                                                      recommended it 73/73 (100%) in the post-test (P < 0.001;
                                                                  Table 1).
Study Population                                                     In onychomycosis, the choice of a systemic treatment was
Participating PCPs were asked about their gender, age, geo-       made by 16/73 (21.9%) PCPs in the pre-test while 54/73
graphic setting (urban, suburban, or rural area), number          (74%) prescribed it in the post-test (P < 0.001). For SGCT,
of years after initial medical certification, attendance to       the use of radiology imaging raised from 18/73 (24.7%) in
post-university training session dermatology during the last      the pre-test to 43/73 (58.9%) in the post-test (P < 0.001;
2 years. Although we had the results of the pre-test of all the   Table 1).
enrolled population, we only retained for statistical analy-         We also observed a decrease of using dangerous manage-
sis the 73 for whom we had the complete sequence of tests         ment in the post-test especially in malignant tumors. Seven
and training. The 65 PCPs who did not completed the entire        dangerous managements were initially proposed in the pre-
study were only compared to the 73 others to determine if         test (4/73 in SSCC, 2/73 in amelanotic SUM and 1/73 in
the two populations could be any different.                       pigmented SUM) then was reduced to 3 after completion of
                                                                  the training program (3/73 in amelanotic SUM), (P = 0.324;
Statistics                                                        Table 3).
Statistical analysis was performed by an independent biostat-        The use of inappropriate/dangerous systemic treatment
istician (GD) who also reviewed the questionnaire before its      was reduced after the training program: from 4/73 (5.5%) to
online launch. Statistical unit was the PCP. Statistical anal-    1/73 (1.4%) in warts (P = 0.085); and from 18/73 (24.7%)
ysis was conducted using the IBM IPSS Statistic software,         to 10/73 (13.7%) in alopecia areata (P = 0.045; Table 3).
version 19 (IBM). Distribution comparisons were made by              A decrease in the unnecessary consumption of medical
the Chi-2 test, Fisher test for qualitative variables, Student    resources was also observed (Table 4). Mycological/bacte-
t test or paired Student t test for quantitative variables. P     riological tests decreased after the training program: from
value <0.05 was considered significant.                           29/73 (39.7%) to only 3/73 (4.1%) in warts (P < 0.001) and
                                                                  from 40/73 (54.8%) to 4/73 (5.5%) in trauma-induced nail
                                                                  changes (P < 0.001). Moreover, emergency referral (urgent
Results
                                                                  second opinion) to dermatologists decreased from 20/73
Training path web link was sent to 10,205 PCPs. One hun-          (27.4%) to 5/73 (6.2%) (P < 0.001) and from 6/73 (8.2%)
dred and thirty-eight PCPs were initially enrolled in the study   to 0% (P = 0.005) in subungual hemorrhage and alopecia
and finished the pre-test. However, only 73 (52.9%) among         areata respectively.
them completed the whole training program. Comparison                Of note, the number of mycological/bacteriological tests
with national statistics disclosed that our tested population,    slightly increased in the post-test (Table 4): 0/73 versus 7/73
as usual in many medical surveys, included a slightly higher      (9.6%) in case of amelanotic SUM (P = 0.03). Similarly,
number of female (51/73 (69.3%); P = 0.0007) and younger          the number of prescriptions of topical antifungals as well
(<40 years-old) (40/73 (54.7%); P = 1.0 10-12) PCPs than          as the number of urgent dermatologist referrals slightly in-
found in their general population in France.                      creased in the post-test in case of nail psoriasis (Table 4):
    Comparing each PCP with himself, we demonstrated              4/73 (5.5%) versus 1/73 (1.4%) (P = 0.085) and 2/73 (2.7%)
that the pre-test mean score was 15.2/20 and raised to            versus 0/73 (P = 0.076) respectively, which was not statisti-
16.9/20 in the post-test (P = 2.25 10-18). Comparison of the      cally significant. We can however observe that the post-test



Original Article | Dermatol Pract Concept. 2023;13(3):e2023170                                                                 3
    Table 1. Pre-to-post-test evolution of correct or compulsory management answers in the panel.
                                                                  Correct or compulsory answers, N (%)
                     Nail disorders                              Pre-test (N = 73)           Post-test (N = 73)          P value
 Wart
    Clinical follow-up                                                6 (8.2)                     19 (26.0)                0.002
 Trauma-induced nail change
    Clinical follow-up                                               16 (21.9)                    33 (45.2)                0.001
    Podiatrist consultation                                          13 (17.8)                    55 (75.3)                0.001
 Onychomycosis
    Mycological or bacteriological test                              36 (49.3)                    53 (72.6)                0.001
    Non-urgent dermatologist second opinion                          27 (37.0)                    13 (17.8)                0.004
    Systemic treatment                                               16 (21.9)                    54 (74.0)              < 0.001
 Squamous cell carcinoma
    Radiology imaging                                                16 (21.9)                    22 (30.1)                0.128
    Urgent dermatologist second opinion                              56 (76.7)                    66 (90.4)                0.012
 Amelanotic nail melanoma
    Radiology imaging                                                39 (53.4)                    14 (19.7)              <0.001
    Urgent dermatologist second opinion                              71 (97.3)                    68 (93.2)                0.122
 Glomus tumor
    Radiology imaging                                                18 (24.7)                    43 (58.9)              <0.001
    Non-urgent dermatologist second opinion                          43 (58.9)                    41 (56.2)                0.369
 Subungual hemorrhage
    Clinical follow-up                                               52 (71.2)                    60 (82.2)                0.057
 Pigmented subungual melanoma
    Urgent dermatologist second opinion                              59 (80.3)                    73 (100)               <0.001
 Alopecia areata
    Non-urgent dermatologist second opinion                          53 (72.6)                    61 (83,6)                0.053
 Psoriasis
    Non-urgent dermatologist second opinion                          58 (79.5)                    60 (82,2)                0.337
    Systemic treatment                                               11 (15.1)                    10 (13,7)                0.407




case of psoriasis nail could have been found more difficult to     delay to initial treatment often long, from 15 months to
identify by the panel of PCPs since it was correctly diagnosed     30 years [8,9]. SSCC, s also often diagnosed late, from 2
in only 45/73 (61.6%) versus 72/73 (98.6%) for the pre-test        to 480 months (mean : 55 months) [10]. These important
(P < 0.001) (Table 2). Lastly, in case of nail unit wart, the      delays might be partially responsible of an apparent worse
rate of urgent dermatologist referral increased from 12/73         prognosis of SUM with a 33% overall survival rate at 15
(16.4%) to 23/73 (31.5%) (P = 0.015) after the training as         years. Moreover, since conservative surgical treatments can
well as the use of radiology imaging which increase from           be offered to early-stage SUM and SSCC, these delays could
3/73 (4.1%) to 13/73 (17.8%) (P = 0.003) (Table 4).                also result in a higher number of amputations and subse-
                                                                   quent disabilities [11,12].
                                                                      Part of the problem could be initial wrong management
Conclusions                                                        strategies by PCPs [13]. However, little is known in the liter-
Most of the studies about SUM, SSCC and, to a lesser extent,       ature about the global knowledge of PCPs about common
SGCT, underline that diagnostic delay is often long and gen-       or functionally important nail diseases [14-16]. For unknown
erates losses of chance for curative and functional surgery in     reasons, the most widely acknowledged nail conditions by
the two cancers and an unnecessary long delay towards func-        health professionals are fungal infections. Indeed, many ony-
tional and pain relief in the latter case. SUM is frequently       chomycoses do exist since it is claimed that about 10 to 50%
discovered at advanced stage and the average reported              of all nail diseases could be due to dermatophytic nail bed



4                                                                      Original Article | Dermatol Pract Concept. 2023;13(3):e2023170
                       Table 2. Pre-to-post test evolution of correct diagnosis in the panel.
                                                                          Correct diagnosis, N (%)
                                                                 Pre-test (N = 73)            Post-test (N = 73)          P value
 Wart                                                               19 (26.0)                      31 (42.5)                0.017
 Trauma-induced nail change                                         24 (32.9)                      70 (95.9)               <0.001
 Onychomycosis                                                      44 (60.3)                      72 (98.9)               <0.001
 Squamous cell carcinoma                                            12 (16.4)                      28 (38.4)                0.001
 Amelanotic subungual melanoma                                      12 (16.4)                      34 (46.6)              <0.001
 Glomus tumor                                                       49 (67.1)                      56 (76.7)                0.097
 Subungual hemorrhage                                               53 (72.6)                      68 (93.2)               <0.001
 Pigmented subungual melanoma                                       62 (84.9)                      71 (97.3)                0.004
 Alopecia areata                                                    49 (67.1)                      48 (65.8)                0.430
 Psoriasis                                                          72 (98.6)                      45 (61.6)               <0.001



                Table 3. Pre-to-post test evolution of “dangerous” management in the panel.
                                                                            “Dangerous” answer, N (%)
                                                                      Pre-test (N = 73)          Post-test (N = 73)       P value
 Wart
   Systemic treatment                                                      4 (5.5)                     1 (1.4)              0.085
 Trauma-induced nail change
   Systemic treatment                                                      5 (6.8)                       0                  0.010
 Squamous cell carcinoma
   Clinical follow-up                                                      2 (2.7)                       0                  0.076
   Topical antifungal                                                           0                        0                   NA
   Other topical treatment                                                 1 (1.4)                       0                  0.157
   Systemic treatment                                                      1 (1.4)                       0                  0.157
 Amelanotic nail melanoma
   Clinical follow-up                                                           0                        0                   NA
   Non-urgent dermatologist second opinion                                 2 (2.7)                     3 (4.1)              0.324
   Topical antifungal                                                           0                        0                   NA
   Other topical treatment                                                      0                        0                   NA
   Systemic treatment                                                           0                        0                   NA
 Glomus tumor
   Systemic treatment                                                           0                        0                   NA
 Subungual hemorrhage
   Systemic treatment                                                           0                        0                   NA
 Pigmented nail melanoma
   Clinical follow-up                                                      1 (1.4)                       0                  0.157
 Alopecia areata
   Systemic treatment                                                     18 (24.7)                  10 (13.7)              0.045

NA = not applicable.


invasion [17]. However, many authors believe that this con-             laboratory tests [19,20]. Trauma-induced nail changes are
dition is often not the primary nail disease and that many of           much more common on toenails with the exception of on-
them in fact complicate a pre-existing nail disease or injury           ychotillomania. Evaluation of nail disease must always be
[18]. Damaged nail by inflammatory nail disease like psoria-            done keeping in mind that any trouble of the foot static or
sis are often secondarily contaminated by dermatophytes that            any use of traumatizing shoes can result in nail injury and
can subsequently be evidenced in the nail table by mycological          chronic changes too often confused with nail fungal infection.



Original Article | Dermatol Pract Concept. 2023;13(3):e2023170                                                                      5
        Table 4. Pre-to-post-test evolution of inappropriate use of medical resources in the panel.
                                                                        Incorrect answer, N (%)
                                                             Pre-test (N = 73)            Post-test (N = 73)           P-value
 Wart
    Radiology imaging                                             3 (4.1)                       13 (17.8)                0.003
    Mycological or bacteriological test                          29 (39.7)                       3 (4.1)                <0.001
    Urgent dermatologist second opinion                          12 (16.4)                      23 (31.5)                0.015
 Trauma-induced nail change
    Radiology imaging                                               0                               0                     NA
    Mycological or bacteriological test                          40 (54.8)                       4 (5.5)                <0.001
 Topical antifungal                                              37 (50.7)                       1 (1.4)                <0.001
    Urgent dermatologist second opinion                           1 (1.4)                        1 (1.4)                 0.500
 Onychomycosis
    Radiology imaging                                             3 (4.1)                        1 (1.4)                 0.154
    Orthopedic surgeon second opinion                               0                               0                     NA
    Urgent dermatologist second opinion                           4 (5.5)                        2 (2.7)                 0.202
 Squamous cell carcinoma
    Mycological or bacteriological test                          9 (12.3)                        1 (1.4)                 0.004
 Amelanotic nail melanoma
    Mycological or bacteriological test                             0                            7 (9.6)                 0.003
 Glomus tumor
    Mycological or bacteriological test                           1 (1.4)                           0                    0.157
    Topical antifungal                                              0                               0                     NA
 Subungual hemorrhage
    Radiology imaging                                             6 (8.2)                        2 (2.7)                 0.071
    Mycological or bacteriological test                           1 (1.4)                           0                    0.157
    Orthopedic surgeon second opinion                             1 (1.4)                           0                    0.157
    Urgent dermatologist second opinion                          20 (27.4)                       5 (5.8)                <0.001
 Pigmented nail melanoma
    Mycological or bacteriological test                           1 (1.4)                           0                    0.157
 Alopecia areata
    Radiology imaging                                             1 (1.4)                        1 (1.4)                 0.500
    Mycological or bacteriological test                          14 (19.2)                       8 (11)                  0.081
    Topical antifungal                                            3 (4.1)                           0                    0.038
    Urgent dermatologist second opinion                           6 (8.2)                           0                    0.005
 Psoriasis
    Radiology imaging                                             2 (2.7)                           0                    0.076
    Topical antifungal                                            1 (1.4)                        4 (5.5)                 0.085
    Urgent dermatologist second opinion                             0                            2 (2.7)                 0.076

NA = not applicable.



    We believe that a wider diffusion of five simple rules can   and painful nail condition and (5) evaluate the static and the
avoid many misdiagnoses: (1) thinking about nail tumor           dynamic of feet for toenail disease and eventually refer to a
when a condition is monodactylic, (2) referring to derma-        podiatrist.
tologist for brown or black but also red or white-yellowish          Our study showed a global poor level of knowledge with
longitudinal nail band, (3) spontaneous nail plate erosion       a relatively high frequency of inappropriate proposed man-
is not banal, (4) referring to dermalogist for non resolutive    agement. We also observed a misuse of medical resources in




6                                                                     Original Article | Dermatol Pract Concept. 2023;13(3):e2023170
many benign conditions. In our view, the rate of pre-test mis-       References
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                                                                         DOI: 10.1111/dth.13032. PMID: 31344289.
egy: more thorough training for amelanotic SUM seems to be
                                                                      4. Phan A, Touzet S, Dalle S, Ronger-Savlé S, Balme B, Thomas L. Ac-
necessary. However, this diagnosis often remains difficult even          ral lentiginous melanoma: a clinicoprognostic study of 126 cases.
for trained dermatologists. High level of prescription of radiol-        Br J Dermatol. 2006;155(3):561-569. DOI: 10.1111/j.1365
ogy imaging and urgent dermatology consultation in nail unit             -2133.2006.07368.x. PMID: 16911282.
viral warts appears to be an unexpected unwanted effect of the        5. Natarajan V, Nath AK, Thappa DM, Singh R, Verma SK. Coex-
                                                                         istence of onychomycosis in psoriatic nails: a descriptive study.
sensibilization of our public about the diagnosis of SSCC. We
                                                                         Indian J Dermatol Venereol Leprol. 2010;76(6):723. DOI:
do not consider this as a poor outcome of our training pro-
                                                                         10.4103/0378-6323.72468. PMID: 21079333.
gram since it is always better to insist on the possible malignant    6. Girisha BS, Shenoy MM, Mathias M, Mohan R. Glomus tu-
counterpart. Maybe an age and disease-duration threshold                 mor of the nail unit. Indian J Dermatol. 2011;56(5):583-584.
could be proposed in our teaching to help counter this effect.           DOI: 10.4103/0019-5154.87163. PMID: 22121286. PMCID:
    Our study has several possible biases. Our sample did not            PMC3221231.
                                                                      7. Jawalkar H, Maryada VR, Brahmajoshyula V, Kotha GK. Sub-
reflect the general population of French PCPs since women
                                                                         ungual glomus tumors of the hand: Treated by transungual exci-
were overrepresented and our population was younger. This
                                                                         sion. Indian J Orthop. 2015;49(4):403-407. DOI: 10.4103/0019
is a common finding in medical practice surveys and prob-                -5413.159611. PMID: 26229160. PMCID: PMC4510793.
ably reflect the greater interest for online educational tools        8. Chakera AH, Quinn MJ, Lo S, Drummond M, et al. Subungual
of young health professionals, who are more often women                  Melanoma of the Hand. Ann Surg Oncol. 2019;26(4):1035-
in our country. As mentioned earlier, we cannot exclude a                1043. DOI: 10.1245/s10434-018-07094-w. PMID: 30565042.
                                                                      9. Talavera-Belmonte A, Bonfill-Ortí M, Martínez-Molina L, et al.
selection bias, yet our questionnaire revealed that only few
                                                                         Subungual Melanoma: A Descriptive Study of 34 Patients. Actas
of them had received a specific training in dermatology in
                                                                         Dermosifiliogr (Engl Ed). 2018;109(9):801-806. DOI: 10.1016/j.
general and on nail diseases during the two previous years. A            ad.2018.06.010. PMID: 30082026.
framing bias cannot be excluded since our teaser message to          10. Dijksterhuis A, Friedeman E, van der Heijden B. Squamous
enter the study specifically mentioned the risk of misdiagnos-           Cell Carcinoma of the Nail Unit: Review of the Literature.
ing nail unit cancer in general and SUM in particular.                   J Hand Surg Am. 2018;43(4):374-379.e2. DOI: 10.1016/j
                                                                         .jhsa.2018.01.010. PMID: 29482957.
    In conclusion, correct diagnosis of a nail disease can be
                                                                     11. Sureda N, Phan A, Poulalhon N, Balme B, Dalle S, Thomas L.
delayed especially in primary care. Onychomycosis is often
                                                                         Conservative surgical management of subungual (matrix de-
over-diagnosed, since there is a lot of commercial communi-              rived) melanoma: report of seven cases and literature review.
cation about it. A short online training focusing on five simple         Br J Dermatol. 2011;165(4):852-858. DOI: 10.1111/j.1365
rules significantly improved the management abilities of sev-             -2133.2011.10477.x. PMID: 21812768.
eral nail conditions including life threatening ones by PCPs.        12. Topin-Ruiz S, Surinach C, Dalle S, Duru G, Balme B, Thomas
                                                                          L. Surgical Treatment of Subungual Squamous Cell Car-
                                                                          cinoma by Wide Excision of the Nail Unit and Skin Graft
Acknowledgements                                                          Reconstruction: An Evaluation of Treatment Efficiency
                                                                          and Outcomes. JAMA Dermatol. 2017;153(5):442-448.
This work is supported in part by grants from Lyon 1 Uni-                 DOI: 10.1001/jamadermatol.2017.0014. PMID: 28384651.
versity (to LT), the Hospices Civils de Lyon (to LT) and by              ­PMCID: PMC5817490.
                                                                     13. Papachristou DN, Fortner JG. Melanoma arising under
the foundation “vaincre le mélanome” (to LT).
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    We thank the URPS for its help in the diffusion of our
                                                                          /jso.2930210405. PMID: 7144198.
questionnaire and training path.                                     14. Iorizzo M. Tips to treat the 5 most common nail disorders: brittle
    We thank Mr Anthony Masson administrator of Claro-                    nails, onycholysis, paronychia, psoriasis, onychomycosis. Derma-
line web site.                                                            tol Clin. 2015;33(2):175-183. DOI: 10.1016/j.det.2014.12.001.
    We thank 138 volunteers who accepted to enter the study.              PMID: 25828710.




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