Urticaria - It's not only itch

摘要

Urticaria is a common presentation in Emergency Department. Most of the time its idiopathic or immune mediated. In a small proportion of cases it may be a symptom of serious medical illness. We report two case of urticaria with underlying medical causes. Case 1: A 33-year-old female presented to emergency with recurrent urticaria, which started 5 months back. Even though it responded to antihistamines, symptoms recurred on discontinuing medicines. No other symptom and no other past medical illness. Clinical examination was unremarkable, except for extensive urticaria. Her laboratory evaluation showed hyperthyroidism, and deranged liver function test (LFT). She was started on carbimazole and symptoms improved after a few weeks. Symptom recurred after 3 months when dose was reduced and promptly relieved on restarting old dose. After few weeks she discontinued her medication and symptom recurred. On restarting the medicine she improved again. Her LFT also improved on follow up. Case 2: One young female was seen in emergency with episodic urticaria for 6 months. She responded to antihistamines but recurred on discontinuing medicine. No significant illness in past. Clinical examination showed anaemia and generalised urticaria. Her laboratory test showed microcytic hypo chromic anaemia and her iron profile was suggestive iron deficiency. Urticaria symptoms improved after she was initiated on iron replacement. Discussion: The above two cases represents two systemic causes of urticaria. Exact mechanism of how these disorder produce urticaria is unknown. In case of iron deficiency, iron therapy even in the absence of anaemia, is found to improve urticaria. The prevalence of thyroid autoimmunity is high in patients with chronic idiopathic urticaria. Mast cell over stimulation by thyroid hormone is thought to be the mechanism behind the urticaria in hyperthyroidism. Physicians should look for systemic causes when patients present with recurrent symptoms.