Hypocomplementemic urticarial vasculitic syndrome, asthma and anaphylactic reaction with ampicillin.

A patient with hypocomplementemic urticarial vasculitic syndrome (HUV) is presented. This is an immunological pathology, limited to skin or multisystemic, that requires a differential diagnosis with erythematosus systemic lupus on the same occasions. The ever-present symptom is skin participation, such as urticaria-angioedema or fixed exanthema; biopsy shows necrotizing venulitis with polymorphonuclear infiltration and leukocytoclastic powder. Typical laboratory data are: diminished C3, C4 and C1q; C1 inhibition can be low or normal; the more characteristic finding is the presence of C1q associated immunocomplexes. Leukocytoclastic necrotizing vasculitis was found in the skin biopsy. During the course of illness (three years) the patient presented moderate cutaneous symptoms and asthma, without other systemic participation. During this period, antihistamines and, occasionally, corticoids were administered with improvement. Moreover, the patient presented urticaria related to ampicillin ingestion, and furthermore, the presence of anaphylaxis to beta-lactam was diagnosed in vivo and specific IgE was found in the laboratory study. This feature was previously observed by other authors; however, we cannot determine why the IgE-mediated allergy to beta-lactam and a complement pathology like HUV are related.