Suction blister fluid histamine in fixed drug eruption.

The histamine concentration was measured from suction blister fluid obtained from normal and lesional skin of 8 patients with fixed drug eruption (FDE) caused by phenazone salicylate and from that of 2 healthy control subjects. In blister fluid samples obtained before peroral challenge with phenazone salicylate, the histamine concentrations were below 5 nmol/l both in uninvolved skin and in sites of previous FDE lesion (sample 0). After challenge, samples were taken from the incipient reaction that was visible after an average of 155 min. Histamine levels were significantly elevated in the blister fluid of 2 out of 8 FDE lesions (200 and 640 nmol/l) but in none of the uninvolved skin (sample 1). Two hours later (sample 2) the histamine levels were elevated in both uninvolved (mean 51.4 nmol/l) and lesional skin (mean 168 nmol/l). After 24 h (sample 3) the corresponding mean value was 25.4 nmol/l for uninvolved skin and 108 nmol/l for lesional skin. The histamine values in the blister fluid from FDE lesions in samples 2 and 3 were significantly higher (p less than 0.05) than those in the control blisters of uninvolved skin. An elevation of histamine levels comparable to that in the uninvolved skin of FDE patients was seen in the 2 healthy control subjects studied. The present study provides direct evidence of early release of histamine from mast cells or basophils in FDE and suggests that histamine is one of the mediators of clinical symptoms of FDE.