Diagnostic procedures for eczema patients.

Of 7887 patients with eczema seen in a private dermatological practice over a period of 2 years and 4 months, a specific final diagnosis was found in 5376 (68%), while a final diagnosis of non-specific eczema was made in 2511 cases (32%). The most common final diagnoses were seborrhoeic dermatitis (1351), contact dermatitis (1317), atopic dermatitis (1009) and nummular eczema (822). Battery patch testing was the initial diagnostic procedure performed, and 897 of the 3164 patients who were patch tested had one or more positive patch tests. In 545 cases, the reactions were considered of relevance to the current dermatitis. Tests for immediate-type allergy were carried out in 618 patients, and 284 of these had one or more positive tests. In 86 patients, these test results were of diagnostic significance. 257 patients with positive patch tests were challenged orally with the relevant substance, and 53 of 156 reacted to metal salts, most commonly nickel, while 25 of 101 reacted to orally ingested balsam of Peru. Among patch-test-negative patients, 66 of 408 had positive reactions to one or more metal salts; 41 of 180 reacted to balsam of Peru, while 15 of 41 reacted to various food additives.