One hundred patients with acute urticaria were prospectively studied over a 2-year period with re-spect to etiology, clinical features and outcome, including the patient’s quality of life using a Thai version of the Dermatologic Life Quality Index (DLQI). Twenty-one patients (21%) turned out to have chronic and 79 acute urti-caria. Itchy sensations had the highest mean DLQI score translating to the highest negative impact on the quality of life. In more than half of the patients, the cause of the acute urticaria could not be identified. The most common identified causes of acute urticaria were infections (36.7%), followed by drugs, foods and insect bite reactions. Among those with acute urticaria, sixteen percent had co-existing angioedema, and one fourth had systemic symp-toms, the most common being dyspnea. Patients with extensive wheals tended to have co-existing angioedema and also a statistically significant higher percentage of systemic symptoms, higher mean pruritus and mean DLQI scores than those with less body surface area involvement. Fifty-six percent of the patients with acute urticaria had complete remissions within 1 week; 78.5%, within 2 weeks and 91.1%, within 3 weeks.