Ashy Dermatosis With Significant Perivascular and Subepidermal Fibrosis

Abstract

To the Editor: Erythema dyschromicum perstans or ashy dermatosis is a chronic hyperpigmentary disease of unknown etiology.1 It presents as ash-colored usually asymptomatic macules located in trunk and proximal extremities. Histopathological findings demonstrate lichenoid dermatitis with vacuolization of basal cells, colloid bodies, and a moderate infiltrate of lymphocytes in the papillary dermis admixed with melanophages.2-4 An 80-year-old man presented to our department with a 4-month history of asymptomatic, progressively increasing in number, blue-gray oval macules over his trunk and proximal extremities, which ranged in size from 3 to 4 cm (Fig. 1). No history of photosensitivity or preceding erythema was found. Darier's sign was negative. Dermoscopy showed small grayish spots of pigment in a diffuse distribution and arranged in a fine linear pattern in some areas, together with whitish areas mimicking regression or scarring (Fig. 2).FIGURE 1: Generalized blue grayish macules scattered over the back.FIGURE 2: Dermoscopy shows dots of grayish pigment and whitish areas.Histologically, the epidermis was slightly hyperplastic with basal cell hyperpigmentation. Numerous melanophages were present around superficial blood vessels, with virtually absent lymphocytic infiltration. Besides, significant perivascular and subepidermal fibrosis was also noted. Masson-Fontana staining confirmed the melanin nature of the pigment present within macrophages (Fig. 3).FIGURE 3: Top: low-power magnification showing a slightly hyperplastic epidermis, numerous perivascular melanophages, and striking fibrosis surrounding vessels and in the papillary dermis (hematoxylin and eosin, ×100). Bottom: abundant melanin in the cytoplasm of basal keratinocytes and in dermal melanophages (Masson-Fontana, ×200).Erythema dyschromicum perstans, also referred to as ashy dermatosis, is a benign disease of unknown origin that occurs more frequently in the Latin American population. Clinically, it is characterized by ash-colored, oval or round, asymptomatic macules that may disappear within several months. These lesions especially involve the trunk and proximal extremities and extend peripherally, usually sparing palms, soles, scalp, nails, and mucous membranes. The histopathologic findings from the active border may show a vacuolar degeneration of the basal cell layer, occasional colloidal bodies, pigment incontinence, phagocytic cells, congestive and dilated vessels, and a perivascular inflammatory lymphohistiocytic infiltrate.1-4 Fibrosis has not been reported as a histological feature for the diagnosis of ashy dermatosis. It is necessary to exclude fixed drug eruptions, lichen planus pigmentosus, postinflammatory hyperpigmentation, idiopathic eruptive macular pigmentation, and dermatosis that present with diffuse hyperpigmentation such as Addison disease or hemochromatosis.5,6 Several treatments such as topical steroids or systemic corticosteroids, antibiotics, ultraviolet light therapy, dapsone, or clofazimine have been tried with an inconsistent efficacy.3 This case is interesting because of the correlation between the dermoscopic and pathologic findings. The pigment showed by dermoscopy arranged in spots and in a fine linear pattern corresponds to the melanophagia appreciated histologically. Otherwise, the white areas similar to regression or scarring appreciated dermoscopically would correspond histologically with the significant fibrosis present in the papillary dermis and surrounding vessels. To our knowledge, there are no previous reports that emphasize this correlation that otherwise could be helpful for the diagnosis of this disease. As a conclusion, dermoscopy could add helpful clues for the diagnosis of ashy dermatosis. José M. Martín, MD Verónica López, MD Esperanza Jordá, MD, PhD Department of Dermatology Hospital Clínico Universitario Valencia, Spain Carlos Monteagudo, MD, PhD Department of Pathology Hospital Clínico Universitario Valencia, Spain Funding sources: None. Conflict of interest: None.