Wells syndrome.

Wells syndrome or eosinophilic cellulitis is characterized clinically by an acute dermatitis resembling cellulitis and histopathologically by dermal eosinophilic infiltration. Various morphological presentations have been described. We report a 32-year-old female with recurrent, erythematous plaques on left forearm of 8 months duration, associated with mild itching that resolved leaving mild hyperpigmentation.

INTRODUCTION

Wells syndrome is a rare condition of unknown etiology and pathogenesis. In 1971, George Wells first described this syndrome as a recurrent granulomatous dermatitis with eosinophilia.[1] The term “eosinophilic cellulitis” was introduced by Wells and Smith in 1979.[2] Wells syndrome is characterized by clinical features of cellulitis and a histopathologic picture of eosinophilic infiltrate of the dermis along with the presence of “flame figures.” The typical clinical presentation of the eosinophilic cellulitis is mildly pruritic, recurrent, cellulite like plaque, although several clinical presentations like urticarial, papulonodular, and vesicobullous lesions have been reported, depending upon the location of the infiltrate. The lesions usually remit and the course is benign except for mild constitutional symptoms. Wells syndrome is associated with a range of disorders like arthropod bite, myeloproliferative disease, colon cancer, reaction to thiomersal-containing vaccination, Churg–Strauss syndrome, hypereosinophilic syndromes, dermographism, onchocerciasis, herpes-simplex infection, immunobullous disease, and drug reaction. While some authors consider Wells syndrome to be a histological reaction pattern,[3-5] others consider it to be a distinctive disease entity.

CASE REPORT

A 32-year-old female presented with an erythematous, edematous plaque on the flexor aspect of left forearm of 10 days duration, associated with a prodrome of malaise followed by itching and burning sensation at the site [Figure 1]. The lesion was small initially, but later on increased to size of about 5 cm × 4 cm. The plaque was pink-red in color at onset that evolved into violaceous color over a period of 10 days and subsided within 3 weeks, leaving mild hyperpigmentation. Past history revealed 15 similar episodes over a span of 18 months. The lesion would recur at the same site with mild constitutional symptoms. The severity of the episodes varied each time – at some times, the patient would require antihistamines and oral steroids for relief. Laboratory investigations including hemoglobin and total leukocyte counts were normal. Absolute eosinophil count was 440 cells/mm3 (normal: 40–440 cells/mm3). Random blood sugar, liver and renal function tests, urinalysis, chest X-ray, and antinuclear antibodies were normal. Histopathologic examination from a biopsy taken from the plaque showed moderately dense superficial and deep perivascular and periappendageal infiltrate of eosinophils and lymphocytes [Figure 2]. Several eosinophils were scattered in the interstitium of reticular dermis and around the deep vascular plexus [Figure 3]. The papillary dermis showed moderate edema. Based on the clinical presentation and the histopathology, a diagnosis of Wells syndrome was made. The patient was given oral prednisolone 40 mg/ day in tapering dose over 4 weeks. The forearm lesion subsided within 20 days, leaving mild hyperpigmentation. No new lesions appeared during treatment and 3 months of follow-up.

Figure 1

Clinical photograph showing erythematous and indurated plaque on the flexor aspect of left forearm below elbow (encircled)

Figure 2

Photomicrograph showing moderately dense superficial and deep perivascular and periappendageal infiltrate of eosinophils and lymphocytes (arrows) (H and E, ×100)

Figure 3

Photomicrograph showing eosinophils scattered in the interstitium of reticular dermis and around the deep vascular plexus (arrow) (H and E, ×400)

DISCUSSION

Wells syndrome is a rare, idiopathic dermatosis with recurrent, erythematous, urticarial plaques that become more indurated and subsequently heal with mild pigmentation. The course of the disease is mild despite occasional constitutional symptoms. Although Wells syndrome is usually sporadic, familial,[6] neonatal,[7] and childhood[8] cases have been reported. There is wide polymorphism in the clinical and histological presentation of the disease, depending upon the nature and location of the infiltrate.[9] Blood eosinophilia may or may not be found. The diagnosis of the Wells syndrome is based on the clinical features and the course of the disease, especially its recurrences and the histopathologic features of eosinophilic infiltration of the dermis.[9] Histopathologically, a dermal infiltrate of histiocytes, eosinophils, and eosinophilic granules occurs between collagen bundles, which form the classic “flame figures.” Classical flame figures were not documented in the histopathology of our case as the patient presented in the resolving phase. Flame figures are not unique to the Wells syndrome and can be found in any disorder with a eosinophil-rich infiltrate such as insect bites, pemphigoid and Churg–Strauss syndrome. The flame figures may disappear after the acute stage with the granulomatous infiltrate becoming more obvious.

The pathogenesis of Wells syndrome appears to be the cause of dysregulated tissue eosinophilia. Peripheral T-cell immunophenotyping studies have shown an increased proportion of CD3+ and CD4+ T cells.[10] These lymphocytes spontaneously release significant amounts of interleukin 5 (IL- 5) which is involved in the pathogenesis of blood and tissue eosinophilia. The eosinophils then degranulate in the dermis, causing edema and inflammation. With immunofluorescent stains, eosinophil major basic protein is identified in the granules of the flame figures. The relationship of Wells syndrome to other idiopathic disorders with eosinophils is unknown. Wells syndrome usually improves dramatically with low-dose systemic glucocorticoids. Dapsone, interferon-alpha, cyclosporine, antihistamines, or minocycline have also proved effective.[11] History and clinical presentation should prompt the clinician to consider the diagnosis of the Wells syndrome, and histopathologic examination should be done for confirmation. The case is being reported for its rarity.