Hormonally exacerbated hereditary angioedema.

Hereditary angioedema is a rare disorder which is associated with an inherited deficiency of the inhibitor of the activated first component of complement. Genetic transmission occurs in an autosomal dominant manner. Affected patients are heterozygotes, and their deficiency is incomplete, many of them having up to 20% of the normal amount of the inhibitor. We describe two cases of C1 esterase inhibitor deficiency occurring in a mother and daughter in whom the symptoms appeared to be related to the menstrual cycle or the taking of the oral contraceptive pill. Although both features have been mentioned in the literature, to the best of our knowledge premenstrual exacerbations have not been documented previously. We examined the likely basis of hormonally exacerbated hereditary angioedema.