Terra Firma Forme Dermatosis – a Report of two Cases and a Review of the Literature

Terra firma-forme dermatosis (TFFD) or Duncan’s dirty dermatosis is a bizarre, acquired, and idiopathic dermatosis. It is characterized by its asymptomatic, yellowish, or brownish dirt-like lesions, resistant to usual washing with soap and water, but disappearing when rubbed with 70% ethyl alcohol or isopropyl alcohol. Swabbing with alcohol is both diagnostic and therapeutic means for this disorder. We present two boys, aged 14 and 11, with asymptomatic brownish, dirt-like lesions on the chest and forearms, respectively. Skin lesions were continuously present for more than a month. Both of the patients had usual hygiene habits. The diagnosis of TFFD was confirmed by rubbing with 70% ethyl alcohol which led to disappearance of the lesions. TFFD often causes much concern in patients and parents of affected children. Since its clinical picture is similar to some other dermatoses, the disease can be misdiagnosed. Therefore, it is important to recognize this dermatosis in dermatological and pediatric practice in order to explain the benign nature of the disease to patients and to avoid unnecessary diagnostic tests.