Case Studies

 Case 4.10 Chronic urticaria and angioedema

A 25-year-old joiner presented with a 12-month history of an intensely itchy 'nettle rash' on his chest and back. The lesions appeared suddenly and lasted from 6 to 12h, to be replaced by new lesions at other sites. The lesions varied in size from a few millimetres to several centimetres. Attacks occurred two to three times each week. In addition, he had experienced four episodes of sudden swelling of lips which took 48h to subside. He said he looked as though he had been punched. He was unaware of any triggering factors and there was no personal or family history of atopy. His general health was excellent and he was not taking any medications. On examination, the lesions consisted of raised, red, irregular patches, some with white centres, and were typically urticarial. General examination was entirely normal.

Laboratory investigations showed a normal haemoglobin and white cell count, with no eosinophilia. His complement C4 and C1 inhibitor levels were normal, excluding hereditary angioedema (see Case 11.5).

Since certain food additives may trigger urticaria and angioedema, he was challenged with tartrazine (a colouring substance) and sodium benzoate (a food preservative) by mouth; neither substance induced a new crop of lesions. The urticaria was fairly well controlled by antihistamines (cetirizine) but he was reluctant to take any tablets on a long-term basis. Three years later, his urticarial lesions are still present, although less severe; their cause is unknown.