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Erythema dyschromicum perstans_0512 Derm Clinic
An otherwise healthy Hispanic woman, age 43 years, presented to the dermatology clinic for evaluation of a rash. The rash had begun approximately 18 months earlier and started as dark spots on her abdomen that had since spread to involve her proximal extremities.
No pruritus or pain was reported, and no new medications were used prior to the onset of the rash. No treatment had been attempted. On clinical examination, numerous ash-gray to blue macules coalescing into patches were seen in a symmetric distribution on the trunk and proximal extremities.
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Erythema dyschromicum perstans (EDP) is a disorder that most commonly affects Latin Americans and Asians. However, there have been cases reported in Caucasians as well, particularly individuals with skin types III and IV.1 Although some researchers claim that EDP affects women more than men, there are no key findings to support this.
The age of onset has a wide range, most commonly affecting those between the first and third decade of life. There have been cases reported in those who were as young as age 1 year and as old as age 80 years.
EDP has no known pathogenesis. It has been suggested that the condition is a cell-mediated immune reaction against an ingestant, which leads to pigmentary incontinence. In 1973, Pinkus claimed EDP was caused by the effects of environmental pollution in genetically susceptible individuals.1,2 The retrospective examination of various patients has led to the development of a variety of possible predisposing factors, none of which is consistent, however. These factors include orally administered radiographic media (barium sulfate), ammonium nitrates, fertilizer, pesticides, fungicides, and such drugs as penicillin and benzodiazepines.2,3
Other possible etiologies include whipworm infections (intestinal parasitosis caused by nematodes) and HIV. Even chlorothalonil from bananas has been raised as a possible cause of EDP.
Genetic research has shown an HLA-DR4 allele association with EDP in some Hispanic patients.4 The major histocompatibility complex region is believed to house the genes responsible for the disease. Examination of immunologic chemistry demonstrates expression of cell adhesion molecules as well as lymphocyte activation molecules. No specific or consistent microbe, drug, or agent has been identified as the cause, and more research is needed in this area.
Numerous laboratory experiments in persons with EDP have shown negative results for bacterial, viral and mycologic studies. Evaluations of such tests as a complete blood count, comprehensive metabolic panel and urinalysis have not shown any abnormalities in patients with EDP.
EDP is a slow, progressive, acquired and chronic hyperpigmentation. The ash-gray to blue macules start small but think big; they progress slowly and eventually grow to cover large areas of the body. The macules and patches may be oval, with their long axes following skin cleavage lines (circular or irregularly shaped).
Macules/patches range in diameter from 0.5 cm to 2.5 cm.1 They are uncommonly surrounded by an erythematous peripheral margin that can measure 1 mm to 2 mm in diameter.1 The macules can cover a wide area of the body and tend to occur in a symmetrical pattern on the trunk, face, neck, and proximal upper extremities. The lesions do not affect mucous membranes and rarely progress to the palms, soles, or scalp.
EDP is generally asymptomatic, but some patients have reported pruritus. For the most part, the disease does not regress in adults; however, there have been a few cases in children in which spontaneous regression has occurred.5,6
Histologic findings will vary depending on the age of the lesion. In the early stage, the erythematous border (active region) will show vacuolar alteration of the basal layer. Necrotic keratinocytes or colloid bodies may be occasionally seen.7 Melanophages will be mingled with a perivascular and/or lichenoid infiltrate of lymphocytes and histiocytes within the dermis.8
Later in the development of EDP, the ash-gray lesions (inactive region) may have a considerable amount of epidermal change; these include atrophy and effacement of the normal pattern of rete ridges.8 There is also a considerable amount of pigment incontinence.
Since its discovery, some researchers and authors have regarded EDP as a variant of lichen planus due to the similarity of their clinical and histologic features. Direct immunofluorescence studies of the active border of EDP have shown immunoglobulin (Ig)M, IgG, and fibrinogen, just as is seen with lichen planus. However, EDP will often only demonstrate fibrinogen at the dermal-epidermal junction.1 Additionally, immunofluorescence studies have shown the dermal infiltrate to be composed of CD4+ and CD8+ T cells, also commonly seen in lichen planus. Making the clinical distinction between the two conditions may be difficult. Lichen planus is usually distinguished clinically by flat-topped papules and plaques, which are features not seen in EDP.
Fixed-drug eruptions (FDEs) must also be in the differential diagnosis. The infiltrate and pigmentary incontinence seen in FDEs may appear very similar to EDP. However, the lesions seen in FDEs are often more circular and brown in color.
Pityriasis rosea, small plaque parapsoriasis, post-inflammatory hyperpigmentation, melasma, erythema multiforme and other drug reactions must also be considered.
EDP is chronic, and there are no effective treatments for the disease. Topical corticosteroids, hydroquinone, and sun protection have been ineffective in treating EDP. Retinoids, vitamin C, vitamin A, chemical peels, UV light therapy, antimarials, and antibiotics have all failed to produce any significant results.1 In a small series, treatment with dapsone and clofazimine (Lamprene) was reported as effective.1
EDP is benign and will not cause death. Lesions have been known to spontaneously resolve in prepubertal children but often chronically persist in adults.5,6 Most patients will be concerned about cosmetic issues related to the disease and may suffer from anxiety and depression. The unpleasant sight of the blue-grayish lesions can cause significant damage to the patient’s self-esteem. As always, it is important for clinicians to pay close attention to the patient’s emotions and psychological distress.
The patient in this case was counseled on the chronic nature of the disease and the poor treatment regimens available. She was given reassurance and strongly advised to use sun protection.
Kerri Robbins, MD, is a resident in the Department of Dermatology at Baylor College of Medicine in Houston.
References
1. Bolognia JL, Jorizzo JL, Rapini RP eds. Dermatology. 2nd ed. St. Louis, Mo.: Elsevier Mosby; 2008:178-179, 940-942.
2. Pinkus H. Lichenoid tissue reactions. A speculative review of the clinical spectrum of epidermal basal cell damage with special reference to erythema dyschromicum perstans. Arch Dermatol. 1973;107:840-846.
3. Schwartz RA. Erythema dyschromicum perstans: the continuing enigma of Cinderella or ashy dermatosis. Int J Dermatol. 2004;43:230-232.
4. Correa MC, Memije EV, Vargas-Alarcón G, et al. HLA-DR association with the genetic susceptibility to develop ashy dermatosis in Mexican Mestizo patients. J Am Acad Dermatol. 2007;56:617-620.
5. Lee SJ, Chung KY. Erythema dyschromicum perstans in early childhood. J Dermatol. 1999; 26:119-121.
6. Paller AS, Mancini AJ. Hurwitz Clinical Pediatric Dermatology. 3rd ed. Philadelphia, Pa.: Elsevier Saunders; 2006:293-294.
7. RP Rapini. Practical Dermatopathology. Philadelphia, Pa.: Elsevier Mosby; 2005:70.
8. Elder DE, Elenitsas R, Johnson BL, et al, eds. Lever’s Histopathology of the Skin. 10th ed. Philadelphia, Pa.: Lippincott Williams & Wilkins; 2009:172-173.
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