UPMC Dermatopathology "Case of the Month" Presentations
UPP - Department of Dermatology, Dermatopathology Unit
Case Authors: Jason G. Whalen, MD; Joseph C. English III, MD; Leena Lourdaraj, MD; Drazen M. Jukic, MD
FEBRUARY 2005 CASE OF THE MONTH
DISCUSSION & DIAGNOSIS
Diagnosis
Erythema Dyschromicum Perstans (EDP), aka Ashy Dermatosis
Discussion
Erythema Dyschromium Perstans, also known as Ashy dermatosis or Dermatosis cinecienta, is a usually asymptomatic, slowly progressive eruption first described in El Salvador in 1957. It is most commonly seen in patients with intermediate skin color (Skin type III/IV), with a majority from Central America. Women are more affected than men, and there is a variable age of onset (primarily 2nd-3rd decades).
The pathogenesis of EDP remains unknown, but there are some reported associations with ammonium nitrate, whipworm infections, HIV, and orally administered contrast medium (barium sulfate). Immunohistochemical studies suggest that T-lymphocytes participate in the origin of this disease.
The clinical features of EDP are oval/circular shaped macules and patches in a symmetric distribution on the trunk, face, neck and proximal upper extremities. The palms, soles, scalp, and mucous membranes are spared. The lesions vary from slate gray to blue-brown pigmentation. Uncommonly, there is a thin, raised, erythematous border that resolves in a few months. The lesions usually follow skin tension lines (Langers lines), as in pityriasis rosea. Occasionally, there can be mild pruritus but the lesions are usually asymptomatic. EDP is a slowly progressive disease over years and usually does not spontaneously resolve. It is not associated with any systemic involvement.
Pathology of EDP reveals vacuolar degeneration in the basal cell layer, occasional colloid bodies, and a variable lichenoid lymphocytic infiltrate in the border of active lesions. In inactive ashy-colored lesions, a considerable amount of dermal melanophages/pigment incontinence as well as variable epidermal change(e.g. atrophy, acanthosis) can be observed.
The differential diagnosis of EDP includes lichen planus, lichenoid drug eruptions, post-inflammatory hyperpigmentation, multiple fixed drug eruptions, macular amyloidosis, maculae cerulae (pubic lice), and macular urticaria pigmentosa.
There are no known effective and established treatments for EDP, primarily because the pigment is primarily in the dermis, and not the epidermis. Multiple unsuccessful treatments include sunscreen, topical retinoids/corticosteroids/Vitamin C, oral antibiotics/steroids/dapsone/antimalarials/griseofulvin and chemical peels. Anectodal evidence showing successful outcomes in small studies has been seen with clofazamine. Lasers that help remove dermal melanin (e.g. Q-switched ruby) may prove to be helpful for this condition. Finally, although rare, there is the hope for spontaneous remission. After refusing to try clofazamine, the patient was given Tri-Luma cream to apply every day for 8 weeks and to follow-up in clinic after that time.