Allergy to cockroach antigens in patients with peptic ulcers and chronic gastritis.

Cockroach allergy was investigated in 10 patients with the endoscopic diagnosis of peptic ulcers and chronic gastritis, all with positive skin reactions to Blatella germanica extract. In all the cases examined, the total serum IgE level was raised, specific serum IgE detectable and both the increased number of eosinophils and IgE-bearing cells found in biopsy specimens of gastric and/or duodenal tissues. The direct provocation test of the gastric mucosa, done under fiberoscopic control, was positive in all patients, in which the immediate oedematous and haemorrhagic reaction was observed after allergen challenge. Seven patients reacted also a few minutes later with abdominal pains and/or nasal and conjunctival manifestations. The provocation with the same cockroach extracts was negative in 4 control patients with peptic ulcers but without symptoms of allergy. In the authors' opinion, cockroach antigens, like other food and inhalant allergens, may be partly responsible for the chronic inflammatory processes as well as ulcerations of gastroduodenal tissues in predisposed persons.