Atopic dermatitis (AD), also known as atopic eczema, is a long-term type of inflammation of the skin (dermatitis). It results in itchy, red, swollen, and cracked skin. Clear fluid may come from the affected areas, which often thickens over time. While the condition may occur at any age, it typically starts in childhood, with changing severity over the years. In children under one year of age, much of the body may be affected. As children get older, the areas on the insides of the knees and elbows are most commonly affected. In adults, the hands and feet are most commonly affected. Scratching the affected areas worsens the symptoms, and those affected have an increased risk of skin infections. Many people with atopic dermatitis develop hay fever or asthma.The cause is unknown but believed to involve genetics, immune system dysfunction, environmental exposures, and difficulties with the permeability of the skin. If one identical twin is affected, the other has an 85% chance of having the condition. Those who live in cities and dry climates are more commonly affected. Exposure to certain chemicals or frequent hand washing makes symptoms worse. While emotional stress may make the symptoms worse, it is not a cause. The disorder is not contagious. A diagnosis is typically based on the signs and symptoms.
For this reason, it is helpful to be evaluated by a dermatologist with a special interest or expertise in scalp and hair disorders, and who is familiar with current diagnostic methods and therapies. Classification
Cicatricial alopecias are classified as primary or secondary. This discussion is confined to the primary cicatricial alopecias in which the hair follicle is the target of the destructive inflammatory process. In secondary cicatricial alopecias, destruction of the hair follicle is incidental to a non-follicle-directed process or external injury, such as severe infections, burns, radiation, tumors, or traction. Primary cicatricial alopecias are further classified by the type of inflammatory cells that destroy the hair follicle during the active stage of the disease. The inflammation may predominantly involve lymphocytes or neutrophils. Cicatricial alopecias that predominantly involve lymphocytic inflammation include lichen planopilaris, frontal fibrosing alopecia, central centrifugal alopecia, and pseudopelade (Brocq). Cicatricial alopecias that are due to predominantly neutrophilic inflammation include folliculitis decalvans, tufted folliculitis, and dissecting cellulitis of the scalp. Sometimes the inflammation shifts from a predominantly neutrophilic process to a lymphocytic process. A cicatricial alopecia with a mixed inflammatory infiltrate is folliculitis keloidalis. Treatment
As mentioned above, primary cicatricial alopecias are classified by the predominant type of inflammatory cells that attack the hair follicles, such as lymphocytes, neutrophils, or mixed inflammatory cells. Treatment strategies are different for each subtype and detailed treatment options are beyond the scope of this discussion. However, certain general principals are reviewed below.