La prevalenza della sensibilizzazione da contatto al latice in pazienti consecutivi sottoposti a patch test

Background: natural rubber latex gloves and mainly their chemical additives are one of the most common causes of allergic contact dermatitis in many occupations. Objective: the aim of this study was to investigate the prevalence of delayed reactions to latex in consecutively patch tested patients. Materials and methods: 2 non-ammoniated latex extracts in 10% petrolatum, with different protein contents (0.48 and 1.28 mg/ml), and a series of latex additives were patch tested. The study was carried out in 2 phases: 695 patients with eczematous dermatitis and 312 subjects with chronic hand dermatitis who frequently used rubber gloves were investigated, respectively during the first and second period. Patients with a personal history of latex contact urticaria were excluded. Those with a positive path test reaction to latex were also prick tested. Results: no strongly positive or doubtful reactions were observed in 5 of the subjects investigated during the first phase (0.7%) and in 2 of those of second phase (0.6%). None of these showed positive reactions to latex additives patches or latex prick test. Conclusions: as delayed sensitivity to natural rubber latex is not frequent, its inclusion in the standard patch test series at present is not justified. Further studies will be needed to explain the reported differences in frequency of positive patch test reactions to latex, examining above all patients who use very often rubber gloves and suffer from chronic contact dermatitis of the hands.