Atopic dermatitis (AD) is a chronic inflammation of the skin that occurs in persons of all ages but is more common in children. AD is a chronic, itching, inflammatory skin disease, which is associated with asthma and/or hay fever and a familial occurrence of these conditions.
The prevalence of AD has risen 3-4-fold over the last 30 years and is now a major public health problem in the seven major markets, with 3% of the US population suffering from AD. It has been reported to affect 10 % of children and accounts for between 10 and 20 % of all visits to dermatologists.
Typical clinical appearance of atopic dermatitis.
There is now considerable evidence that colonization or infection with S. aureus is a triggering or exacerbating factor in AD. Superantigens produced by the bacteria stimulate keratinocytes and T-lymfocytes, and trigger the inflammatory process. The inflammation leads to an impaired skin barrier function. Furthermore, endogenous antimicrobial peptides are low in patients with AD, thus leading to a vicious cycle of S. aurues involvement in the disease (see diagram). Superantigens also act as potent inhibitors of steroid action, thus possibly leading to steroid resistance.
Different contributing factors in the development of atopic dermatitis
The use of topically administered AMPs for control and normalization of the bacterial and fungal flora is thus a logical and attractive method for interfering with the pathogenesis of AD. It is well established that treatment of AD with steroids in combination with antibiotics is more effective than use of steroids alone. In the light of current therapies, endogenous AMPs will add an important new and significant therapeutic modality to current treatments without the risk of inducing bacterial resistance.