[Mastitis revealing Churg-Strauss syndrome]

Churg-Strauss syndrome often involves the skin, and this may sometimes reveal the disease.

A 25-year-old woman was referred to a gynaecologist for inflammation of the right breast with breast discharge. Cytological analysis of the liquid showed numerous inflammatory cells, particularly polymorphonuclear eosinophils and neutrophils. Ultrasound examination of the breast was consistent with galactophoritis. CRP was normal, and hypereosinophilia was seen. The patient was subsequently referred to a dermatology unit. Skin examination revealed inflammation of the entire breast, which was painful, warm and erythematous; the border was oedematous with blisters. Necrotic lesions were also present on the thumbs and knees. Skin biopsy of the breast showed a dermal infiltrate with abundant infiltrate of polymorphonuclear eosinophils, including patchy necrosis and intraepidermal vesicles. Histological examination of a biopsy sample from a thumb revealed eosinophilic granuloma and leukocytoclastic vasculitis. The patient was also presenting asthma, pulmonary infiltrates and mononeuropathy at L3, consistent with Churg-Strauss syndrome.

Breast involvement in Churg-Strauss syndrome is very rare (only one other case has been reported). This is the first case in which the breast condition revealed the disease. Cutaneous involvement of the breast is, however, also compatible with Wells' cellulitis. The lesions quickly disappeared with 1mg/kg/d oral prednisolone.