A retrospective analysis of contact allergy to lanolin.

Lanolin is often stated to be an important sensitizer but some of the available literature is based on the analysis of high-risk patients. To analyse the frequency of contact allergy to lanolin (wool alcohols) in a central London teaching hospital patch-test population. Review of 24,449 patients recorded on our database during 1982--96 who were tested with a standard series containing 30% wool alcohols. The mean annual rate of sensitivity to this allergen was 1.7%. The wool alcohols-allergic group contained a higher proportion of females (P < 0.05), and the mean age of both males and females (48.4 and 49.2 years) was higher than that of non-wool alcohols-allergic patients (41.4 and 35.9 years; P < 0.0005). There was no difference in atopic eczema status between these groups. The highest prevalence of allergy to wool alcohols was among patients with lower leg dermatitis (6.0%; 95% confidence interval, CI 4.46--7.54), followed by those with anogenital dermatitis (3.23%; 95% CI 1.81--4.65). There was an unexplained decline in the rate of positive patch tests to Amerchol L-101. However, some patients who reacted to this were negative with wool alcohols, so it may be a useful additional test reagent. The mean rates of allergy to Eucerin (0.65% per annum) and 50% hydrogenated lanolin in petrolatum (1% per annum) were low, and we no longer use these as test reagents. This study illustrates that lanolin sensitization has remained at a relatively low and constant rate even in a high-risk population (i.e. patients with recent or active eczema).