Angioedema and oral contraception.

BACKGROUND

Oral contraceptives can precipitate attacks of hereditary angioedema (ANE) or induce acquired forms.

OBJECTIVE

We studied 5 patients who had an ANE which had begun under oral contraception and disappeared after stopping the pill.

METHODS

We explored the clinical and biological characteristics of these patients.

RESULTS

The symptoms developed during the first year or later after starting contraception; the patients reported relapsing swelling of the lips, hands, larynx and abdomen. All women had normal serum C4 and C1 inhibitor (C1Inh) antigen levels, but a lowered C1Inh activity, with a marked protein cleavage on the immunoblot. The suppression of the pill was associated with the regression of the edema and normalization of C1Inh function.

CONCLUSIONS

The mechanism of these ANE is unknown. The could be due to a modulation of C1Inh expression upon androgens or an imbalance between coagulation proteins favoring C1Inh cleavage by its target proteases.