Recent advances in the investigations of the molecular basis of hypohidrotic ectodermal dysplasia (HED) and incontinentia pigmenti (IP) are reviewed. A new member of TNF-ligand, ectodysplasin (EDA), its receptor, EDAR, and EDAR-associated death domain (EDARADD), have been isolated. Mutations of these genes have been identified as the cause of X-linked and autosomal forms of HED. NEMO/IKKγ gene deficiency has been shown to cause IP. Recent reports have elucidated that HED and immunodeficiency (HED-ID) is also derived from mutations in exon 10 of the NEMO/IKKγ gene. These data not only confirm the important role of EDA/EDAR signal trunsduction in regulating the morphogenesis of the ectoderm but also provide the unique view that NF-κB activation through NEMO/IKKγ is crucial in the development of skin appendages and the immune system.
Recently in Japan, misunderstandings about the pathogenesis of atopic dermatitis (AD) and the strategies for the treatment of this disease, especially about the use of topical steroid, have led to a rapid increase of severe cases of AD caused by inadequate treatment. This prompted us to establish and distribute standard guidelines for AD therapy. In this guideline, the necessity of dermatological training to examine severe cases of AD is emphasized. It is stated that the present standard therapies for AD consist of the use of topical steroid and tacrolimus ointment (only for adult patients) for inflammation and emollient for dry and barrier—disrupted skin as the first line of attack, anti-histamines and anti-allergic drugs for pruritus, avoidance of apparent exacerbating factors, psychological counselling, and advice about daily life. The importance of correct selection of topical steroid according to the severity of the lesion is emphasized.