Background: Positive patch test reactions to natural rubber latex (NRL) have been interpreted as allergic or irritant by different groups. Additives to the NRL test solution have also caused positive reactions in previous studies.
Objectives: Five centres of the British Contact Dermatitis Group conducted a prospective study on the prevalence of type IV hypersensitivity to NRL, using ammonia-preserved NRL solution for testing.
Patients and methods: A total of 2738 consecutive patients were patch tested. Where clinically indicated, specific IgE was measured or a prick test done.
Results: Twenty-seven patients (1%) had a positive patch test reaction to NRL, which was considered to be allergic and of current relevance in 19 (70%) patients. Fourteen of these also had a positive prick test or specific IgE. Thirteen patients (48%) were male, 19 (70%) atopic and 13 (48%) had eczema on their hands.
Conclusions: We conclude that delayed-type hypersensitivity to NRL is a problem for a proportion of patients with eczema, particularly on their hands, and that patch testing with ammonia-preserved NRL can be recommended to identify these patients. Patients with a positive patch test should be investigated for contact urticaria to NRL.