Cutting fluid dermatitis

174 consecutive patients with suspected cutting fluid dermatitis were investigated in 2 occupational dermatology clinics. 43% showed allergic reactions which were thought to be relevant to their dermatitis. Irritant contact dermatitis occurred in 63%, but only in 21% was it thought to be the sole diagnosis. Biocides, especially formaldehyde releasers, were the commonest cause of allergic reactions in a cutting fluid patch test series.