Erythema dyschromicum perstans in phototype II women: three unusual clinical cases studied with electron microscopy

ARTICLE

ejd.2010.1241

Auteur(s) : Severino PERSECHINO¹, Cristiano CAPERCHI¹, Giorgia CORTESI¹ giorgia.cortesi@libero.it, Flavia PERSECHINO¹, Salvatore RAFFA², Federica PULCINI³, Antonella TAMMARO¹, Maria Rosaria TORRISI²

¹ Dermatology Unit

² Department of Experimental Medicine

³ Department of Histopathology, S. Andrea Hospital, II School of Medicine, University of Rome Sapienza, Via di Grottarossa, 1035, 00189 Rome, Italy

Erythema dyschromicum perstans (ashy dermatosis) is a condition of unknown etiology and pathogenesis. It is a chronic skin disorder, characterized by asymptomatic hyperpigmented macules of various sizes on the face, trunk and extremities. It typically occurs in the second decade of life and generally affects those with phototype IV skin. The age range affected is wide, in both Latin America and around the world [1].

We report our experience of three Caucasian patients, phototype II, affected by this pathology.

All the patients presented numerous gray-blue-colored macules, extending over the trunk, back, neck, forehead, cheeks or extremities (figure 1E). Histological examination of a skin biopsy demonstrated an epidermis with moderate compact hyperkeratosis and many melanophages in the papillary dermis (figure 1A). Electron microscopy showed an epidermis that appeared characterized by vacuolization of the basal keratinocytes and widening of intercellular spaces with retraction of desmosomes. The dermis showed numerous melanophages and perivascular inflammatory infiltrate (figure 1 B-D).

In all patients, treatment with dapsone (100 mg daily) was initiated. During the next 3 months, a marked decrease in pigmentation was observed. In two patients there were no new lesions, while in one patient, discontinuation of therapy resulted in a recurrence of the eruption.

Ashy dermatosis was an entity sui generis. Several terms, such as erythema dyschromicum perstans (EDP), lichen planus pigmentosus, and idiopathic eruptive macular pigmentation have been introduced, describing cases with similar clinical features [2]. The main source of confusion in the literature stems from the fact that there is no consensus on the exact nature of these conditions… some authors consider ashy dermatosis and EDP to be one disease, and use the terms been interchangeably. Others have noted a great similarity between EDP and lichen planus pigmentosus, and regard ashy dermatosis and EDP as variants of lichen planus [3]. The prevalence and the incidence of this pathology is unknown, the literature indicates that ashy dermatosis is most common in people of phototype IV. So, patients with phototype II are uncommon [4].

In the early stages, lesions are characterized by blue-gray macules with raised, erythematous borders, most commonly located on the face, neck, trunk, and upper limbs. In the late stages, the patches turn gray-blue with ill-defined borders. The lesions vary in size from 3 mm to very large confluent patches [5].

The histopathology of EDP is not pathognomonic. The active lesions display vacuolar degeneration of basal cells and pigmentary incontinence, with many melanophages in the upper dermis. Dermal blood vessels are covered with an infiltrate of lymphocytes and histiocytes. In the inactive macules, incontinence of pigment predominates, whereas the cellular infiltrate and vacuolar degeneration of the basal cell layer may range from minimal to intense [6].

Electron microscopy of these lesions is little described in the literature. We think that it is useful for the diagnosis, because the histopathology of EDP is not pathognomonic, nor are laboratory tests. Only the clinical features, histological examination and electron microscopy can give a certain diagnosis.

No treatment of choice is presently available. A number of treatment modalities have been attempted, but all with poor responses. Dapsone is effective in polymorphonuclear-rich dermatoses, as well as lymphocyte-rich dermatoses. It has also been shown to suppress neutrophil migration and the respiratory burst and it interferes with T-cell immunity. It possibly plays a role in the regulation of immune responses involved in the pathogenesis of EDP [6].

This report suggests the therapeutic efficacy of dapsone in the treatment of EDP. Nevertheless, more reports and studies are necessary.

Disclosure

Financial support: none. Conflict of interest: none.

References

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