C3 and dermatitis: Skin biopsy was performed for Patients 3, 4 and 6, which actually helped us on determining the type of reaction: Patient 3 had an eosinophilic spongiosis dermatitis with negative immunofluorescence, Patient 4 had a leucocytoclastic vasculitis with IgA deposits, and Patient 6 had a superficial dermatitis with dermal swelling and granular C3 deposits in the vessel’s walls on direct immunofluorescence.