Association between thyroid autoimmunity and recurrent angioedema in children.

BACKGROUND: The association between thyroid autoimmunity (TA) and idiopathic isolated angioedema (or angioedema without urticaria) has not been evaluated in either children or in adults up until now. We, therefore, aimed to investigate underlying or concomitant TA and/or autoimmune thyroid disease in children diagnosed with recurrent idiopathic angioedema.

METHODS: Children who were consecutively diagnosed with recurrent idiopathic histaminergic acquired angioedema (IH-AAE) between January 2011 and January 2014 constituted the case group. A standard diagnostic and therapeutic algorithm was applied to all the patients with recurrent IH-AAE. Thyroid autoantibodies and thyroid function tests were measured in all the patients with recurrent IH-AAE and in healthy control groups. Prophylaxis with an antihistamine was started for patients with frequently recurrent IH-AAE.

RESULTS: Eighty consecutive children with recurrent IH-AAE (49 boys; median age, 8.3 years) and 80 healthy children (39 boys; median, 8 years) were enrolled in this prospective, case-control study (p > 0.05 for age and sex). The IH-AAE group was significantly different than the control group with respect to TA (13.7% versus 2.5%, respectively; p = 0.009) but was similar with respect to autoimmune thyroid disease (3.7% versus 0%, respectively; p = 0.2). The median follow-up of the recurrent IH-AAE group was 34 months (range, 12-45 months). Patients with recurrent IH-AAE with and those without TA were not different with respect to either the need or the duration of antihistamine prophylaxis (p > 0.05 for both).

CONCLUSIONS: Recurrent IH-AAE may be related to or associated with TA and/or autoimmune thyroid diseases in some children. However, exploring to see whether this association is a causal link or just an epiphenomenon deserves further investigation and longer follow-ups.