CASE AND RESEARCH LETTERS Satisfactory Response to Phototherapy in Pigmented Purpuric Dermatosis

Pigmented purpuric dermatoses (PPD) are a group of eruptive disorders characterized by petechiae and pigmentation affecting principally the lower limbs. These disorders follow a benign and chronic course punctuated by remissions and exacerbations; the etiology is unknown. Histopathology reveals a perivascular lymphocytic infiltrate and red blood cell extravasation in the early stages and hemosiderinladen macrophages in mature lesions. Various treatments have been used, including include oral and topical corticosteroids, ciclosporin, pentoxifylline, oral bioflavonoid preparations, ascorbic acid, and phototherapy; results have been variable. Phototherapy is a widely used dermatologic treatment that has been shown to be effective in patients with PPD. We report a case in which PPD lesions resolved completely after narrow-band (NB) UV-B therapy. The patient was a 74-year-old man who presented with somewhat itchy lesions in the lumbosacral region, buttocks, and thighs that had developed 3 months earlier (Fig. 1). He had no medical history of interest). Skin biopsy showed a perivascular lymphocytic infiltrate in the superficial dermis and the basal layer of the epidermis and extravasation of red blood cells. No significant abnormalities were found in complete blood count, liver or kidney function tests, protein electrophoresis, or biochemistry. Antinuclear antibodies and cryoglobulins were not detected on analysis. A diagnosis of pigmented purpuric lichenoid dermatosis of Gougerot and Blum was established, and NB--UV-B treatment was started with a frequency of 3 times per week following the standard phototherapy protocol for the patient’s skin phototype. The starting dose was 150 mJ/cm with 20% increments in sessions 2 and 3 followed by 10% increments per session up to the maximum tolerated dose. Complete clearance of the lesions was observed after 20 sessions and the patient was changed to a bi-weekly phototherapy