Relevance and Reproducibility of Positive Patch-Test Reactions to Lanolin
Several dermatologists have shown disdain for the idea that lanolin is a major sensitizer. Kligman stated in a 1998 article, “The hue and cry over the high frequency of lanolin allergy is an egregious example of misplaced zeal and science.” This was a follow-up to his 1983 paper, in which he pointed out the lack of information regarding lanolin allergy in the general population, stating that sensitization rates in patients existed only for those with dermatitis. He quoted a study by Sulzberger and colleagues, who assessed 12 healthy subjects and found no positive patch-test reactions to anhydrous lanolin (as is). In an attempt to address this issue, Kligman recruited 943 women with no history of skin problems to undergo patch testing with hydrous lanolin, Eucerin, and 30% wool alcohols in petrolatum. Excluding irritant reactions, none of the women had positive patch-test results. Kligman concluded that lanolin was a weak sensitizer and proposed that previously reported high prevalence rates were due to false-positive results, either from poor interpretation of patch tests or from hyperreactive skin (angry-back syndrome).
Several studies have evaluated the reproducibility of positive reactions to lanolin. Edman and Moller found that only 20 of 33 patients with documented positive patch-test reactions to lanolin had positive reactions upon repeat testing. This loss of sensitivity to lanolin was also documented by Carmichael and colleagues, who reported that of 37 patients with prior positive patch–test reactions to lanolin, only 41% retained their sensitivity when retested 5 years later. In a large multicenter German study measuring concordance, 1,285 patients were patch-tested concomitantly on both sides of the back with 10 allergens, including wool alcohol 30% pet. Sixty-four (0.05%) had an allergic, questionable, or irritant reaction to wool alcohols (30% pet) on one or both sites of the back. Less than 30% of these 64 subjects had patch test results that read as allergic on both sites of the back whereas the largest percentage of subjects (38%) had an allergic reaction on one site and a negative reaction on the other. Reasons proposed for the loss of patch-test positivity included false-positive primary test results, poor patch-test reproducibility, and loss of allergic contact response. Importantly, nonreproducibility or nonconcordance or both have been described with several antigens other than lanolin.[45–47] Gollhausen and colleagues found that up to 44% of reactions to 39 antigens (including lanolin) in 35 patients were nonreproducible. Brasch and colleagues double-tested 1,285 patients with 10 allergens, including lanolin, and found that approximately 40% of reactions to lanolin were nonreproducible; nonreproducibility with other antigens ranged from 20% for nickel to 60% for formaldehyde.
Dermatitis. 2008;19(2):63-72. © 2008 American Contact Dermatitis Society
Cite this: Lanolin Allergy: History, Epidemiology, Responsible Allergens, and Management - Medscape - Apr 01, 2008.