Erythema annulare centrifugum - Submitted on: Tuesday December, 27, 2005

Contributed by:Shaofeng Yan, MD. PhD, N/A

Erythema annulare centrifugum (EAC) was first described by Darier in 1916. It is characterized by an annular erythematous eruption with trailing scales. It is classified as one of the figurate or gyrate erythemas.

Definition: Erythema annulare centrifugum (EAC) is a cutaneous annular erythematous lesion with fine scale on the inner margins of their rims. The pathogenesis is unknown. It may be associated with drug, connective tissue disorders, bacterial, viral, parasitic, fungal infection, or underlying malignancy, etc1.

Clinical Features: Erythema annulare centrifugum typically begins as an erythematous papule that extends peripherally and fades centrally to form a firm annular lesion with delicate scale on the inner margins of their rims (Fig 1). They may be asymptomatic or mildly pruritic2.

Histology: Figures (Click on an image for a larger view) Figure 1: Annular erythematous plaque with delicate scale. Figure 2: Low power magnification shows dense superficial perivascular dense infiltrate. Figure 3: The epidermal changes of EAC are focal parakeratosis and mild spongiosis. Figure 4: Tight perivascular lymphocytic infiltrate Histological features of erythema annulare centrifugum are focal parakeratosis, spongiosis, superficial perivascular dense infiltrate of lymphohistiocytes and rarely eosinophils (Fig 2). Focal parakeratosis and slight spongiosis lead to the clinical delicate scale (Fig3). The clinical firmness is a consequence of slight edema of the papillary dermis. The perivascular lymphocytic infiltrate is well demarcated with a coat-sleeve distribution (Fig 4).

Treatment: EAC is usually self-limited. A search for and treatment of the underlying disorder is the primary therapy. Topical steroids usually are effective but do not prevent the occurrence of new lesions. Systemic or injection steroid therapy is effective, but the eruption can return once steroids are withdrawn.

Bibliography: 1. McKee, PH, et al, Pathology of the Skin with clinical correlations, 3rd edition, 2005, 263-265 2. Harrison PV, et al. The annular erythemas, Int J Dermatol, 1979, 18; 282-290

 

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