[Perianal dermatitis and its benign simulants].

Perianal dermatitis is one of the most common proctological disorders. Concerning the etiology, three different types of dermatitis must be distinguished-the most common irritative contact dermatitis, atopic dermatitis and allergic contact dermatitis. The correct diagnosis is essential for adequate and successful treatment. A variety of benign and malignant disorders must be considered in the differential diagnosis of anal dermatitis. Dermatitic clinical disorders which do not respond to therapy should always be biopsied.