Lexicon for Atopic Dermatitis

This is a lexicon for Atopic Dermatitis.
Click on a letter and discover all the related terms and their definition.

A B C D E F G H I J K L M N O P Q R S T U V W X
  • Hand eczema

     

    Eczema appearing on the hands, and thus generally caused by a repeated exposure to a contact allergen, either due to professional activity or not.  
     
  • Hanifin and Rajka

     

    Jon Hanifin (USA) and Georg Rajka (Norway) are two eminent dermatologists who are famous for their proposal of criteria to facilitate the diagnosis of atopic dermatitis in 1979. This is used in daily practice for difficult cases, and in clinical research to ensure that everyone is referring to the same condition. The "Hanifin and Rajka" criteria are commonly used by dermatological researchers. 
     
  • Hapten

     

    An immunological term used to describe allergens with very low molecular mass. Allergens in contact eczema are generally haptens.
     
  • Hay-fever

     

    A popular term used to designate rhinitis caused by pollen allergy (occasional rhinitis).
     
  • Heliotherapy

     

    Treatment employing exposure to natural sunlight. Whereas photo-therapy uses artificial ultraviolet light (UVA or UVB or both), sun therapy uses the sun's natural light, particularly at hydrotherapy or climate therapy centers. Atopic dermatitis is improved by heliotherapy and photo-therapy; this has been proven under medical control.
     
  • Herpes

     

    A viral disease, caused by a virus from the class herpesviridae, HSV-1 or HSV-2. There are several varieties of herpes: recurrent herpes of the face (cold-sores), genital herpes (a sexually transmitted disease), and severe herpes in some cases (in new-borns, immunosuppressed patients, etc.). 
    Atopic dermatitis can expose patients to a severe form of herpes, known as eczema herpeticum (see term), which requires general antiviral treatment. 
     
  • Herpetiform dermatitis

     

    A fairly rare bullous auto-immune disease, typified by small bullae, with an easily recognizable appearance in biopsies, with deposits of IgA at the top of dermal papillae. Herpetiform dermatitis has no connection to atopic dermatitis
     
  • Histamine

     

    A natural substance containing certain cells: basophils that are found in the blood, and mastocytes that are found in certain tissues including the skin. The release of histamine in the skin, caused by various stimuli, triggers an urticaria lesion (a raised red and itchy area on the surface). Anti-histamines (known as anti-H1 as they are specific to the H1-receptor for histamine) are effective against urticaria. However, they do not help atopic dermatitis, apart from to have a general calming effect. 
     
  • Histiocytosis

     

    A disease caused by the proliferation of certain skin cells known as hystiocytes. 
     
  • HLA system

     

    (Human Leukocyte Antigen) The main system for human histocompatibility, it is comprised of molecules carried by every cell in the organism, which are different from one person to the next (except in identical twins). The HLA system is important in two areas: 
    - Transplant medicine: a donor organ has much more chance of being accepted by the body if both donor and receiver have similar HLA systems; 
    - Vulnerability to certain diseases. Certain HLA groups are predisposed to certain diseases. For example, the HLA B27 group is prone to certain types of rheumatism. 
    -
     
  • Homeopathy

     

    Homeopathy began in the 19th century, founded by Samuel Hahnemann. It is a medical system based on very different ideas to those of conventional medicine.  Some people believe that it is able to change the way the body works, but there is no proof of its efficacy. In practice, homeopathic treatment alone cannot be relied upon to improve the symptoms of atopic dermatitis.
     
  • Household dust

     

    Term describing the presence of microscopic mites (dermatophagoides) in the home environment, which may cause respiratory allergies. Dust-mites are generally found in curtains, rugs and bedding. In the case of atopic dermatitis without respiratory symptoms, removing dust from the home environment has little effect. 
     
  • Hydrotherapy treatment

     

    A stay at a hydrotherapy center, where water from a mineral source is used to treat certain conditions.
    In France, hydrotherapy treatments last three weeks and are reimbursed by social security. 
    Atopic dermatitis is one of the dermatological conditions most commonly treated by hydrotherapy, both for children and adults. Hydrotherapy treatment for dermatological conditions combines water treatments (baths, showers), body wraps, controlled sun exposure, psychological support and information/education workshops. 
     
  • Hygienic hypothesis

     

    A hypothesis which states that allergies are caused by excessive hygiene at the start of life. Children who grow up in "clean", urban environments and have little contact with bacteria, often find their immune system becomes allergic and turn on their own bodies, rather than fighting real infections. The hygiene hypothesis gained some traction a few years ago. Certain medical writers believed that this explained the increase in allergies, including atopic dermatitis, in western countries. The hypothesis remains unproven. However, we should not believe that children must be exposed to infection in order to avoid allergies. Such an attitude has many disadvantages, and likely no real benefits.
     
     
  • Hyper-IgE

     

    A syndrome involving a congenital immune deficiency, which causes sensitivity to certain infections and a higher level of IgE in the blood. This syndrome was described by Dr Rebecca Buckley, and is often known as Buckley syndrome, or Job syndrome. IgE levels are higher in atopic dermatitis, but not as high as in Hyper IgE.
     
  • Hyperlinearity

     

    Excessive visibility of lines on the palm of the hand, which is one of the minor (less important) criteria for atopic dermatitis.
     
  • Hyperpigmentation

     

    A darker tint to the skin, which can be a symptom of certain systemic conditions (Addison's disease, or adrenal insufficiency), or of certain skin conditions such as melasma. It may also result from prolonged inflammation, as seen in certain cases of atopic dermatitis.
     
  • Hypoallergenic

    That reduces the risks of allergies.

A B C D E F G H I J K L M N O P Q R S T U V W X