Thirteen cases were retrieved from literature (ver material suplementario). From the seventeen cases included, 14 (82%) were females (Table 2). The median age was 56 yo. (interquartile range IQR36-78), with a median duration of disease of 6 mo. (IQR1-12). Lesions were frequently generalized (47%), or distributed mostly in lower limbs (41%), characterized as plaques (64.7%), papules (52.9%), with a purpuric (70.6%) and erythematous (64.7%) color. Lesions were mostly pruritic (88.2%), with local or distal edema and angioedema (64.7%), symptoms used for follow-up control. Dermoscopy findings were purpuric dots and globules immerse in an irregular orange-red background (Fig. 3a and b). Laboratory results showed a median of eosinophil count of 3.4 x 109/L (IQR0.8–4.3) and RCP of 13.75mg/L (IQR10.0–30.1). The most frequent treatment was oral corticosteroids (82.4%), mostly prednisone (47.1%) with a median dose of 30mg (IQR20–60). Recurrence of lesions after the tapering or discontinuation of oral steroids was frequent (70.6%). The median time of follow-up with no recurrence of lesions was 6 months (IQR1–12).

Figure 3.

(a) Dermoscopy of case 2 lesion: purpuric fine and coarse dots in a red-orange background. (b) Dermoscopy of case 4 lesion: purpuric fine dots in a red-orange background.

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Our patients were mostly females, with pruritic, purpuric and erythematous papules and plaques mostly in the lower limbs, with local or distal edema (Fig. 1a to c). These symptoms are very similar between the patients described in other case reports (Sup. Table 1) and those presented by Sawada et al.2

The histological findings, first described first by Chen et al.,1 and repeated in the following reports, found in all cases necrotizing vasculitis of small dermal vessels with fibrinoid necrosis, eosinophilic infiltration along the dermis with minimal or no leukocytoclasia (Fig. 2a and b). The epidermis is usually normal except for occasional spongiosis with eosinophilic infiltration.1

Figure 2.

(a) Case 1 histology: diffuse infiltration of eosinophils dispersed and invading necrotized superficial blood vessels. (b) Case 2 histology: fibrinoid necrosis of superficial blood vessels surrounded by eosinophils.

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Eosinophilia2,7 was important, but not essential8,9 with a median blood count of 3.4 x109/L (Table 2) without correlation to severity of symptoms; different from other disorders in which eosinophilia is even greater, such as HES and episodic eosinophilic angioedema.6

Dermoscopic findings, spots and purpuric globules in an irregular red-orange background (Fig. 3a and b), have been described in other forms of vasculitis, such as urticarial vasculitis.10 The purpuric spots and globules correspond to damage superficial dermal vessels with extravasation of red blood cells (necrotizing vasculitis).10 As fibrinoid necrosis is difficult to find in histology, dermoscopic areas of vascular damage would help with the biopsy location.

Based on the findings described by previous authors, and presented in this review, we propose as major criteria: (i) erythematous-purpuric and pruritic plaques and/or papules; (ii) fibrinoid necrosis of dermis vessels with infiltration of eosinophils into the dermis and/or vessel walls in histology; (iii) response to systemic corticosteroids and/or high potency topical corticoids. Among the minor criteria, we suggest: (i) local or distal edema/angioedema; (ii) eosinophilia; (iii) purpuric spots on dermoscopy; (iv) recurrence of lesions after suspension and/or tapering of treatment with corticosteroids; (v) exclusion of another entity that explains the invasion of eosinophils in the skin. The diagnosis would be made with three major criteria and at least one minor criteria, or two major criteria and at least three minor criteria. The clinical and histologic findings are mandatory.

The differential diagnoses are mainly HES, Wells syndrome, and episodic eosinophilic angioedema.1,5 They are all characterized by invasion of eosinophils in the dermis of the affected skin, however no necrotizing vasculitis is found.6 Churg–Strauss syndrome (CSS) is characterized by a spectrum of neutrophilic vasculitis in ANCA-positive patients at one end, to eosinophilic vasculitis in ANCA-negative patients at the other end, whereas a mixed infiltrate of both eosinophils and neutrophils is most often found. Patients with RCEV might represent an ANCA-negative CSS end, then follow-up is mandatory11

The management of RCEV is challenging because the use of corticosteroids is effective, but recurrence is common after tapering of full doses.4 Therapy with 0.5mg/kg/day of oral prednisone can be initiated, with tapering of doses at 2 weeks to the minimum necessary to maintain remission.2 Some authors have proposed Indomethacin,8 Tacrolimus,12 and Sutaplast Tosilate,13 for the RCEV maintenance treatment (Table 2).8,13 Nevertheless, dapsone has been shown to be effective in the control of similar conditions such as eosinophilic cellulitis, eosinophilic fasciitis, etc.6 We propose the use of dapsone as a long-term alternative treatment after tapering of corticosteroids when recurrence occurs.