There are two clinical types of cow's milk protein allergy: the immediate and the delayed type. The immediate type usually presents within minutes after the ingestion of cow's milk protein with urticaria, angio-oedema, vomiting or an acute flare of atopic dermatitis and is present in slightly more than half of the patients with cow's milk protein allergy. Delayed reactions such as atopic dermatitis or gastrointestinal symptoms like proctocolitis or enteropathy usually present after hours or days.