Exogenous oestrogen as an alternative to food allergy in the aetiology of angioneurotic oedema.

Although frequently reported as an aetiology for chronic angioneurotic oedema or urticaria, food allergy is often a diagnosis proposed in the absence of more convincing evidence, as illustrated by the disappointing results of eviction regimens. We report a series of women with an initial diagnosis of food allergy, but in whom the role of oral contraceptives was subsequently demonstrated. Detailed medical history was obtained from 26 young women presenting with chronic angioneurotic oedema or urticaria initially attributed to food allergy, but in whom C1-esterase inhibitor (C1 INH) deficiency was demonstrated. We investigated the effects of oral contraception on C1 INH levels, C1 INH activity and clinical symptoms of these patients. Discontinuation of oral contraception induced an increase in C1 INH levels and C1 INH activity, associated with recovery or marked improvement of the clinical symptoms formerly attributed to food allergy. The relatively high frequency of women taking cyproterone acetate in this population appeared to be a remarkable finding. Replacement of the initial contraception containing ethinylestradiol by a progestogen maintained or even accentuated these good therapeutic results. Exogenous oestrogens, such as those contained in most oral contraceptives, may play an iatrogenic role in the aetiology of chronic angioneurotic oedema or urticaria.