PS69 The girl with the dirty face: terra firma forme dermatitis?

Abstract

A 29-year-old unmarried woman presented to the dermatology department with persistent brownish-grey dirt-like skin lesions over her face and neck for the previous 4 months. A history of adequate washing of the face was present. The patient reported being unable to clear off lesions with soap and water. A history of three similar milder episodes in the last 4 years was present, for which she had consulted various doctors, but the lesions always recurred. Cutaneous examination revealed brown-grey thick, velvety, reticulated plaques over the whole face and neck area. Alcohol swab test was done and the lesions wiped off. A diagnosis of terra firma forme dermatitis or dermatitis neglecta was considered and the patient and parents counselled. After 6 months the patient presented again with her face in a similar condition. Alcohol swab again cleared all lesions. The patient was admitted and biopsy done. Histopathology showed mild orthokeratosis and focal hyperkeratosis, with anastomosing rete ridges at places. The papillary dermis showed a mild lymphomononuclear infiltrate around blood vessels. Masson–Fontana special stain revealed increased melanin pigment. Probing revealed various psychological issues and she was started on medication along with cognitive behavioural therapy and counselling. Terra firma forme dermatitis was first described by Duncan et al. in 1987 to denote brownish dirt-like lesions resistant to washing. Very few cases have been reported in the literature. It is believed to be an acquired, benign disorder of keratinization primarily due to delay in maturation of corneocytes and melanin retention. It has clinical and histological overlap with dermatitis neglecta or may denote a continuum. Alcohol swab test may be diagnostic and therapeutic. Although the diagnosis may be clinical and easy to make, if the condition is recurrent, management is difficult and requires long-term psychological support as well as resolution of the underlying psychological issues.