In 365 children and 213 adults the characteristics of atopic dermatitis isolared by Hanifin and Rajka were analysed in relation to a family history of allergy. A positive history in both parents and/or their families was associated with higher IgE titres. Earlier appearance of skin changes more frequent occurrence of urticaria. Allergic respiratory diseases. Cheilitis. And in women, nipple eczema. These changes were less frequent and the IgE titre was lower in patients with one atopic parent. And even less frequent for lower IgE entre in patients with no family history of atopic disease. Although the latter difference was sometimes slight.