The following cases are reported because of some fallacies connected with the patch tests.
Report of Cases
Case 1.—A farmer's wife, 51 years of age, was hospitalized because of a severely infected acute dermatitis of the face, neck, and arms. As the patient's original dermatitis was suspected to be a contact dermatitis, numerous patch tests were performed, including oleoresins of weeds and molds.* Positive patch tests repeatedly were observed with oleoresins from Alternaria and Trichophyton gypseum. They consisted of erythema and swelling, reached a maximum after 48 hours, and faded away after two more days. There was never an eczematous dermatitis or vesiculation. Intradermal tests with commercial Alternaria and Trichophyton extracts produced minor delayed reactions, consisting of small papules of a few millimeter in diameter. Several other intradermal tests caused similar delayed reactions.
Histological Examinations.—Biopsy was done at the site of a patch test reaction provoked by
EPSTEIN S, PINKUS H. Misleading Patch TestsReport of Two Cases. AMA Arch Derm. 1957;75(2):260–261. doi:10.1001/archderm.1957.01550140104016