Initial cutaneous manifestations consistent with mononeuropathy multiplex in Churg-Strauss syndrome.

BACKGROUND Churg-Strauss syndrome (CSS), also known as allergic granulomatous angiitis, is a rare entity that is characterized by systemic vasculitis in patients with a history of asthma. Patients with CSS show a marked peripheral blood eosinophilia, but the pathogenesis remains unknown. OBSERVATIONS A retrospective review was performed in 9 cases of CSS in whom cutaneous findings were present as an initial manifestation. All 9 patients had purpura and petechiae as well as severe pain and paresthesias of the lower extremities. Four patients (44%) used leukotriene receptor antagonists to treat their asthma, and 3 (75%) of them developed CSS within 3 months. Five patients (56%) were positive for perinuclear antineutrophil cytoplasmic antibodies before therapy, but in all 5 the levels of perinuclear antineutrophil cytoplasmic antibody normalized. Serum IgE levels were elevated in all patients before treatment but decreased after treatment. Histologically, all patients demonstrated leukocytoclastic vasculitis and eosinophilic infiltration. Eight biopsy specimens (73%) revealed marked eosinophilia around the nerve fibers in the dermis. Palisading granulomas in association with vessel-based changes were present in 4 (36%) of 11 biopsy specimens. CONCLUSIONS These characteristic cutaneous clinical patterns that are consistent with the presence of mononeuropathy multiplexes in the lower extremities may help physicians establish an earlier diagnosis. Both eosinophils and IgE, as well as perinuclear antineutrophil cytoplasmic antibodies to some degree, likely participate in skin lesion development in CSS. Furthermore, there appears to be a correlation between treatment with leukotriene receptor antagonists and the onset of CSS in some cases.