[Clinical and experimental observations on idiopathic urticaria due to the contact with heat]

This study describes the probably eleventh case, mentioned in literature, of acquired heat contact uticaria in an otherwise healthy young woman. With regard to true contact induction heat contact urticaria clearly differs from the more common cholinergic uticaria. On the other hand, heat contact urticaria is completely analogous to cold uticaria because of the exposure area, reversible blocking by unphysiological prolonged heating of the skin, sensitivity to antihistamines and resistance to corticosteroids. In this case, whealing of the skin occurred on exposure to heating of 39 degrees C for 5 min. With a temperature of 44-46 degrees C, The shortest time for wheal induction was 3-5 sec. At 70 degrees C, the shortest time for maximal reaction was only a split second. An "optimal temperature" for wheal induction could not be determined. Local anaesthesia with 2% Xylocain caused a considerable blocking of wheals. Histamine and cholinergic drugs showed normal skin reactions after intradermal injection. Antihistamines administered parenterally or perorally were highly effective. Corticosteroids, however, given systemically in high doses proved to be ineffective. During our observations, a spontaneous remission appeared with a clinical symptom-free state; on unphysiological high temperature stimulus, however, contact uticaria could still be demonstrated. The pathogenetic uniformity of sporadic heat contact urticaria and problems of therapeutical controls are discussed.