Terra firma-forme dermatosis: a retrospective review of 31 patients.

Terra firma-forme dermatosis is an idiopathic condition characterized by acquired, dirtlike plaques despite normal hygiene. A diagnosis can be reached by removing lesions with gentle alcohol swabbing. Although Terra firma-forme dermatosis was first described more than 20 years ago and is thought to be not uncommon in clinical practice, it has never been systematically studied. There are few publications about this condition, including no case series of more than six patients. In particular, little is known about the incidence, peak age groups, and most common locations of Terra firma-forme dermatosis. A retrospective review was conducted to identify cases of Terra firma-forme dermatosis in a single-provider practice consisting of 55% pediatric and 45% adult patients. Thirty-one patients with Terra firma-forme dermatosis were identified, including 10 who presented with Terra firma-forme dermatosis as their primary concern. Only two patients were older than 17 years. The median duration of lesions was 4 months. The most common lesion locations were the neck, ankles, and face. Before presenting to the dermatology clinic, three patients had undergone endocrine evaluations, and four had been prescribed topical corticosteroids. Terra firma-forme dermatosis is relatively common and most often occurs in children on the neck or posterior malleolus. This series exemplifies the importance of recognizing Terra firma-forme dermatosis so as to provide rapid relief for patients and avoid unnecessary tests and treatments.