Dermatological diseases of the external male genitalia

The urological examination of male patients includes an inspection of the external genitalia whereby a variety of dermatological alterations can be found. Not all dermatological findings are of clinical relevance. Pearly penile papules and heterotopic sebaceous glands are examples of normal physiological variations. Most penile melanotic macules, angiokeratomas, fibromas and angiomas do not have to be treated; however, penile skin lesions may also be symptoms of other diseases, such as circinate balanitis in Reiter's syndrome and multiple angiokeratomas in Fabry's disease. A typical manifestation of reactions to various drugs is the fixed drug eruption of penile skin. The differential diagnosis of various forms of balanoposthitis may be difficult and requires histological investigations (e.g. plasma cell balanitis or Zoon's disease). In contrast, the clinical manifestation of lichen sclerosus et atrophicus is easy to recognize. The clinical relevance of this disease is due to phimosis and problems during sexual intercourse.