Lexicon for Atopic Dermatitis

This is a lexicon for Atopic Dermatitis.

  • T Lymphocyte


    A variety of lymphocyte with the fundamental role of providing delayed immunity (see delayed hypersensitivity) and cooperating with B lymphocytes which produce antibodies. There are many subsets of T lymphocytes, named after their surface markers (for example, T CD4+) or their role, (e.g. T-effectors, T-regulators). T lymphocytes that stimulate immune responses are known as T-helpers. It is likely that in atopic dermatitis there is some kind of imbalance in T-helper (TH) lymphocytes. TH2 lymphocytes dominate TH1 lymphocytes, which encourages the production of IgE. In fact, immune regulation in atopic dermatitis is a very complex field and not enough is currently known about it. Certainly, immune regulation disorders are not independent from epidermal abnormalities.   
  • T-helpers


    See TH1 and TH2
  • T-regulators


    A subset of T cells which help to maintain immune responses at the correct level preventing them from growing out of control. A deficiency in T-regulator lymphocytes causes excessive immune responses: auto-immune diseases and possibly allergies.
  • T-regulators


  • Tachyphylaxis


    A pharmacological term that is not commonly used. It describes the concept that when a drug is too commonly or inappropriately used, it loses its efficacy. For example, local corticosteroids should not be applied more than twice a day. 
  • Tacrolimus


    Tacrolimus (commercially known as Protopic®) is a topical anti-inflammatory drug. It acts in a different way to corticosteroids. It is a calcineurin inhibitor. The same molecule when used for systemic treatment acts as a powerful immunosuppressant (Prograf®), used to prevent organ rejection in transplants. Topical tacrolimus is an effective and well-tolerated treatment for atopic dermatitis. As with all drugs, one should always follow the indication, counter-indications and directions for use. Sometimes when beginning treatment with tacrolimus, sensations of heat or discomfort may be felt, but they are generally moderate and temporary.  
  • TH1 and TH2


    T means T lymphocytes (differentiated in the thymus), which are blood cells responsible for many immune reactions.
    H means "helper". Thus, TH1 and TH2 are T lymphocytes that work together and with other cells to increase immune responses. They are often called CD4 or CD4+ lymphocytes, as they express the surface protein CD4. 
    There are several subsets of T-helper lymphocytes, known by number: 
    TH1 are primarily involved in defense against certain microbes, 
    TH2 are involved in stimulating B cells to produce antibodies, including IgE.
    In atopic dermatitis and atopy in general there is an imbalance between these subsets; TH2s are more numerous or more active than in non-atopic subjects. 
  • Thalassotherapy


    Treatment using seawater. This generally involves a visit to a center for baths, treatments and a special diet. Thalassotherapy is a sort of "well-being cure" for healthy people with no medical aim.
  • Therapeutic education


    A collection of measures facilitating an improvement in patients' awareness of their condition and its treatment. Compared to a traditional medical consultation, therapeutic education aims to mobilize the maximum number of people (doctors, nurses, psychologists, etc.) and leave patients plenty of time to express their concerns and receive specially-adapted information. Therapeutic education improves the patient's understanding of the condition, reduces anxiety, and facilitates correct treatment. The result is an improvement in the condition's symptoms and its psychological and social consequences. 
    See also, Workshops, Schools, and the Atopic Dermatitis Foundation's website www.fondation-dermatite-atopique.org
  • Therapeutic education (ETP)

    Therapeutic education is a set of practices intended to allow the patient to acquire skills so as to actively take responsibility for the treatment of his or her own disease, manage related care and perform supervision of the disease in partnership with caregivers.

  • Therapeutic education workshop

    A forum dedicated to the treatment of patients suffering from chronic diseases: psoriasis, asthma, diabetes  ...

  • Thermal care or treatment

    Thermal waters have properties known to be beneficial, in particular for eczema.
    Spas specialized in dermatology have developed appropriate treatment techniques, which allow for sustained improvement after 18 days of care.
    The cost of the treatment can be reimbursed to the extent of 65% of the conventional base rate (in France).

  • Thermalism


    Treatment using mineral spring waters. The word thermal indicates that the water is warm, but this is not always the case. Thermalism is a medical treatment carried out at hydrotherapy centers that have been built around water sources where the water has special properties. Each center has its own special indications: Avène, La Roche-Posay, and Uriage specifically treat skin conditions; Aix-les-Bains, Dax and others treat rheumatism, and La Bourboule and others respiratory conditions.
    Thermal or hydrotherapy treatments obey strict medical regulation: they are prescribed by a doctor and reimbursed by medical insurance. They last three weeks, including a program of treatments that are carried out under direction from medical specialists. 
    Alongside this traditional program, the patients benefit from a holistic medical, psychological, educational and environmental support for their condition.  
  • Thymus


    An organ of the immune system located at the base of the neck. 
  • TNF-alpha


    Tumor Necrosis Factor. This factor has many biological properties, but is primarily involved in chronic inflammatory conditions such as rheumatism or even psoriasis. Anti-TNF antibodies are effective treatments for these inflammatory conditions. 
  • Toll-like receptors


    Receptor resembling the roll receptor of the Drosophila fly, which help cells to recognize microbes and thus trigger defense reactions. These receptors are part of innate immunity (see this term). There are around ten types of toll-like receptor or TLR. They are important in dermatology as they are found in keratinocytes, and represent the first line of defense against infection. They also have other properties.
  • Topical immunosuppressor

    This is a new class of local drugs for eczema.
    (They are not dermocorticosteroids.)
    They are very effective, but must be used with caution and on doctors' orders.

  • Transepidermal water loss


    In its normal state, the epidermis loses small quantities of water through evaporation - this is known as insensible water loss, as the subject does not notice it is happening. This evaporation is a good marker for epidermal integrity and barrier function. If these are compromised, much more water escapes the epidermis and insensible water loss increases. One of the ways to prove a treatment has improved the condition of the epidermis is to measure transepidermal water loss, which should have diminished. 
  • TSLP (cytokine)


    Thymic Stromal Lymphopoietin. TSLP was initially isolated from a strand of thymic cells, hence its name. However, it is also secreted by other cells, including keratinocytes. Its role is to activate lymphocyte differentiation in favor of TH2 cells. It is currently thought that TSLP plays an important role in atopic dermatitis, as it is activated by epidermal abnormalities, and stimulates TH2 cells, and thus triggers stimulation of B lymphocytes to produce antibodies including IgE. Thus, TSLP is a link between epidermal abnormality and allergic inflammation