We report a study of the sensitization rate to sesquiterpene lactone (SL) m
ix at the National Skin Centre, Singapore. This is a retrospective review o
f 1256 patients who were patch tested to SL mix (0.1%) from January 1995 to
December 1997. 18 out of 1256 patients (1.43%) reacted positively to SL mi
x. Their ages ranged from 13 to 58 years (average 33.8 years). There were 1
5 Chinese, 2 Indian and 1 Malay patients. There was a female preponderance,
with a female: male ratio of 3.5:1. The most common clinical presentation
were dermatitis of the hands (8; 44%), face (5; 28%), and generalized invol
vement (5; 28%). After extensive evaluation, only 2 patients had a positive
patch test reaction that was of current clinical relevance. 13 patients ha
d concomitant sensitization to other allergens. The 3 commonest concomitant
allergens were nickel, balsam of Peru and fragrance mix. In our series, SL
allergy is observed to be more common in females and the mean age is lower
compared to the classical Compositae dermatitis. The sensitization rate is
comparable to other studies, although the clinical relevance is only 11%.