ORIGINAL ARTICLES   

Giornale Italiano di Dermatologia e Venereologia 2005 February;140(1):27-32

Copyright © 2005 EDIZIONI MINERVA MEDICA

language: English, Italian

Immediate contact reactions to patch test allergens

Belloni Fortina A. ¹, Piaserico S. ², Alaibac M. ², Peserico A. ²

¹ Department of Pediatrics University of Padua, Padua, Italy 2 Department of Dermatology University of Padua, Padua, Italy

Aim. Patch test allergens of standard series may induce immediate contact reactions in closed patch test. We have assessed the incidence of immediate contact reactions to various patch test allergens and evaluated the association between immediate and delayed contact reactions to the same allergen.
Methods. Four-hundred and four patients (144 males and 260 females, mean age 40.4±17.6 years) with suspected contact dermatitis underwent closed patch tests. Patients were examined at 30 min for immediate contact reactions and at 48 and 96 h for delayed contact reactions.
Results. Two-hundred and eighty-two (69.8%) patients developed at least one immediate contact reaction. The substances that most frequently yielded a positive immediate contact reaction were: balsam of Perù (61.4%), fragrance mix (35.1%), paraben mix (2.2%), carba mix (2%). No association was found between immediate and delayed patch test reactions to the same allergen, except for Kathon CG and diaminodiphenyl-methane. Age, sex and frequency of atopy were not significantly different in patients who developed immediate contact reaction and patients that did not.
Conclusion. The high number of immediate contact reactions to standard patch test allergens in patients without any clinical manifestation related to contact urticaria, seems somehow to reduce the usefulness of closed patch testing in the diagnosis of contact urticaria.