Simultaneous sensitivity to fragrances.

BACKGROUND: Cinnamal/cinnamic alcohol and isoeugenol/eugenol are pairs of related fragrance chemicals found in Fragrance Mix I (FM I), and thus are routinely tested in combination with other fragrances in the European standard patch test series. Their close structural similarity makes the occurrence of simultaneous sensitivity within these chemical pairs likely, although at present there are no robust data to support this hypothesis. OBJECTIVES: To establish the frequency of simultaneous reactions to these fragrance chemicals in patients with suspected fragrance allergy attending a contact dermatitis clinic; to provide evidence in support of proposed metabolic pathways; and to determine whether including all four separately in FM I is necessary to avoid missing a diagnosis of fragrance allergy. METHODS: We analysed retrospectively the records of patients patch tested to the European standard series during the 15-year period 1984-98 for positive reactions to FM I. In a subset of patients tested to the constituents of FM I, positive reactions to cinnamal, cinnamic alcohol, isoeugenol and eugenol were sought. Data were analysed using 2x2 contingency tables (Fisher's exact test). RESULTS: During this period, 23,660 patients were tested to the European standard series, of whom 1811 (7.7%) had positive reactions to FM I. Of the 1112 patients tested to the constituents of FM I, 934 had positive reactions to at least one constituent (total 1324 positive reactions to constituents). Of these 934, 826 also had positive reactions to FM I itself; 108 were negative to FM I but reacted to one or more of its constituents. One hundred and seventy-eight patients did not react to any of the breakdown constituents of FM I; 34 of these had positive reactions to FM I itself. Of 139 patients allergic to cinnamic alcohol, 87 were also allergic to cinnamal (63%), compared with 108 (11.1%) of 973 cinnamic alcohol-negative patients (P<0.00001). Of 231 patients allergic to isoeugenol, 50 were also allergic to eugenol (22%), vs. 109 (12.4%) of 881 isoeugenol-negative patients (P=0.0002). CONCLUSIONS: These data support in vitro experiments indicating that cinnamal and cinnamic alcohol may generate a common hapten and are consistent with the view that simultaneous sensitization to isoeugenol and eugenol occurs to a limited extent, despite their being metabolized via different pathways. In view of the substantial number of isolated reactions to each of these fragrance chemicals, all four should continue to be included separately as constituents of FM I.

Analysis of para-phenylenediamine allergic patients in relation to strength of patch test reaction.

BACKGROUND: Despite having a positive patch test reaction to para-phenylenediamine (PPD), some patients continue to dye their hair, while others are forced to give up or abandon this practice. This difference in patient behaviour could be due to the degree of sensitization. OBJECTIVES: To establish whether the ability to continue dyeing hair in PPD allergic patients is related to the strength of patch test reaction. To note differences in other clinical features in relation to the strength of patch test reaction. METHODS: We analysed retrospectively the patch test records of 400 sequential PPD-positive patients for the strength of patch test reaction (+, ++, +++) and different clinical features. Data were analysed using Cochran-Mantel-Haenszel chi2 tests. RESULTS: There was a strong linear relationship between the strength of patch test reaction and continuation with hair dyeing. Patients were more likely to report a history of hair dye reaction with increasing strength of patch test reaction. There was no difference in strength of patch test reaction in relation to age, site of rash, occupation (hairdressing) or history of atopic eczema. Overall concomitant reactivity with related aromatic amine allergens (benzocaine, N-isopropyl-N-phenyl-para-phenylenediamine, para-aminobenzoic acid) was infrequent. CONCLUSIONS: Patients with stronger patch test reactions (++, +++) are more likely to have a clear history of reacting to hair dye and are less likely to still be dyeing their hair.

Immediate contact reactions to fragrance mix constituents and Myroxylon pereirae resin.

We have studied patients who have positive-patch test reactions to fragrance-allergic screening substances fragrance mix (FM) or Myroxylon pereirae resin (balsam of Peru) for immediate contact reactions to the standard FM, the constituents of the FM and Myroxylon pereirae resin. In the fragrance-positive subjects (n = 60), there were positive immediate contact reactions to Myroxylon pereirae resin in 56.6% and to FM in 11.6%. In a control group (n = 50) of eczematous, patch test-negative patients there were positive immediate reactions to Myroxylon pereirae resin in 58.0% subjects and to FM in 12.0%. The absence of a significant difference between the fragrance-allergic group and control group is in keeping with a non-immunological basis for the majority of the immediate reactions seen.

The frequency of fragrance allergy in patch-tested patients increases with their age.

BACKGROUND: The most likely age of sensitization to fragrance chemicals is unknown. OBJECTIVES: To investigate the frequency of allergy to the 8% fragrance mix (FM) in each decade of life in patients undergoing patch testing for the investigation of skin symptoms. METHODS: Patients (n = 23 846; 14 104 female and 9742 male) underwent patch testing to a standard series between 1 January 1984 and 31 December 1998. All data were recorded on a computerized database. RESULTS: We found that 8.4% of females and 6.4% of males were allergic to the FM. The frequency of fragrance allergy was low in the first two decades of life (2.5-3.4%). It gradually increased in females after the age of 20 years to peak in the 60s at 14.4% of those tested, with a decline to 11.6% in the 80s. The prevalence in males rose more slowly and peaked at 13.7% in the 70s, declining to 10.8% in the 80s. The youngest patients sensitized were aged 2 years. CONCLUSIONS: These findings support the hypothesis that allergy to fragrance results from a combination of repeated environmental exposure and age-related susceptibility factors.

Allergic contact dermatitis from occupational exposure to ranitidine hydrochloride.

Contact sensitivity to ranitidine hydrochloride has been demonstrated in 6 of 8 symptomatic exposed pharmaceutical manufacturing employees; a 7th has been found to be sensitized to ranitidine base. Although closed manufacturing processes diminish the risk of such sensitization, operatives with potential exposure should be made aware of the importance of avoiding skin contact.

Contaminating resin acids have not caused the high rate of sensitivity to oak moss.

Commercially available oak moss absolute patch test material has recently been shown to contain resin acids of the type found in colophony (colophonium). We wished to assess whether the high frequency of positive patch tests to oak moss absolute at this institute was likely to reflect significant contamination by resin acids. The rate of positive reactions to colophony among our oak moss-allergic patients patch tested during 1984-2000 was retrospectively investigated. 25395 patients were tested to the European standard series during this period and 1963 (7.7%) were allergic to the fragrance mix. 342 of these patients were allergic to oak moss absolute, of whom 73 (21.3%) were allergic to colophony. In comparison, 115 (13.4%) of 861 fragrance mix-positive but oak moss-negative patients were allergic to colophony (p = 0.0002, Fisher's exact test). This strongly statistically significant association between oak moss absolute and colophony shows only a small increase in rates of allergy to colophony in oak moss-positive patients. Thus we conclude that contaminating resin acids have not alone caused the high rate of sensitivity to oak moss.

Dermatitis caused by physical irritants.

BACKGROUND: Although physical irritant contact dermatitis (PICD) is a common occupational dermatosis, it is one of the least well understood because of its multiple types, lack of diagnostic test, and the many mechanisms involved in its production. OBJECTIVES: To characterize the materials and mechanisms of physical irritation of the skin. METHODS: We did a retrospective analysis over the past 20 years of all patients with a diagnosis of PICD at St John's Institute of Dermatology Contact Dermatitis Clinic. RESULTS: Of the 29,000 patients who attended the clinic over the study period, 392 patients were diagnosed with PICD and of these, 335 files were analysed. CONCLUSIONS: Our findings show that PICD accounted for 1.15% of all patients attending the contact clinic over the study period. Diverse occupations and materials were implicated. The most common cause of PICD was low humidity due to air-conditioning, which caused dermatitis of the face and neck in office workers due to drying out of the skin.

Comparative frequency of patch test reactions to topical antibiotics.

BACKGROUND: Neomycin, clioquinol and fusidic acid are all topical antibiotics widely used in dermatological practice in the U.K., either as a single agent or in combination with topical corticosteroids. However, an adverse effect of topical antibiotics is contact sensitization. OBJECTIVES: To examine the frequency of positive patch test reactions to fusidic acid, clioquinol and neomycin. METHODS: To compare the frequency of allergic patch test reactions over 1 year, we patch tested all patients attending the St John's Institute of Dermatology contact dermatitis clinic for one calendar year with fusidic acid, neomycin and clioquinol. RESULTS: We patch tested 1119 patients. Positive patch test reactions to neomycin were noted in 40 patients (3.6%), compared with eight patients (0.7%) to clioquinol and three patients (0.3%) to fusidic acid. The frequency of medicament allergy to neomycin was thus five times more common than to clioquinol and ten times more common than to fusidic acid. Although fusidic acid is not part of our extended standard series, it is in our medicaments series. Therefore, in the second part of our study, we reviewed all cases of positive patch test reactions to fusidic acid over the last 20 years. We found that the frequency of hypersensitivity has decreased since the early 1980s despite increasing usage; the current average frequency being 1.62 patch-tested patients per year (1.45%) of those patch tested to the medicaments series). The most common diagnosis in such patients was stasis dermatitis (54.2%). CONCLUSIONS: The frequency of fusidic acid allergy in an eczema population is low and is comparable with published data from over 10 years ago.

Fragrance as an occupational allergen.

Sensitization to fragrance is believed to occur mainly outside the workplace. This study addresses the frequency of fragrance allergy in patch test patients of differing occupations during a 15 year period. The occupation most strongly associated with fragrance allergy in both sexes was health care work (positive tests in 11.7% of males and 10.4% of females). Retired individuals also had high rates of fragrance allergy (11.6% of males and 14.5% of females), and the prevalence of sensitization increased with advancing age. Health care workers and metal workers had statistically significantly higher rates of allergy to eugenol than did workers in other occupations. Food handlers had significantly higher rates of allergy to cinnamal and cinnamic alcohol. These findings suggest that sensitization to fragrance occurs more frequently in an occupational setting than is generally understood and could have implications for preventive measures.

Photoallergic contact dermatitis is uncommon.

BACKGROUND: Despite the enormous increase in sunscreen use, allergic contact (AC) and photoallergic (PA) reactions to ultraviolet (UV) filters are considered rare. OBJECTIVES: To analyse the data from 2715 patients who underwent photopatch testing at St John's Institute of Dermatology during the period 1983-98. METHODS: A retrospective analysis of all positive photopatch test episodes was undertaken with the results retrieved from the environmental dermatology database and further verified with the original archived patch test documentation for each individual patient. RESULTS: In 111 patients with positive reactions (4.1%), there were 155 AC or PA reactions to allergens in the photopatch test series. Eighty PA reactions were observed in 62 (2.3%) patients (32 men and 30 women, age range 28-75 years), with UV filters accounting for 52 positive reactions (65%), drugs 16 (20%), musk ambrette 11 (14%) and the antiseptic trichlorocarbanilide one (1%). The most common UV filter photoallergen was benzophenone-3 with 14 positive results, followed by benzophenone-10 (n = 9), isopropyl dibenzoylmethane (n = 6), p-aminobenzoic acid (PABA) (n = 5), octyl dimethyl PABA (n = 5), butyl methoxydibenzoylmethane (n = 4), isoamyl methoxycinnamate (n = 2), ethyl methoxycinnamate (n = 2), octyl methoxycinnamate (n = 2), amyl dimethyl PABA (n = 2) and phenylbenzimidazole sulphonic acid (n = 1). A similar number of AC reactions to UV filters was detected in this study. Thus 49 patients (1.8%) had a total of 75 reactions: 51 due to UV filters and 24 as a result of exposure to fragrances and therapeutic agents. Benzophenone-10 accounted for 13 AC reactions and benzophenone-3 for eight reactions. Twenty-two patients had a PA reaction alone, whereas 19 patients had chronic actinic dermatitis and 15 patients polymorphic light eruption (PLE) in addition. Thus, 34 of the 62 patients (55%) had a preceding underlying photodermatosis. CONCLUSIONS: These results show a low yield of positive photopatch tests. Thus, despite the large increase in the use of UV filters over the last decade, the development of PA reactions remains rare. Furthermore, most of the common UV filter photoallergens identified in this study, including PABA, amyl dimethyl PABA and benzophenone-10, are now rarely used in sunscreen manufacture, while isopropyl dibenzoylmethane was voluntarily removed from the market in 1993. Currently, benzophenone-3 is the commonest contact photoallergen still in widespread use. In contrast, the UVB filter octyl methoxycinnamate, used in a number of sunscreens, produced only two positive PA reactions in 12 years of testing. Nevertheless, although these reactions are extremely rare, patients with photodermatoses such as PLE and chronic actinic dermatitis do represent a group of patients at increased risk of developing photoallergy. Further photopatch test series should be regularly reviewed and updated, as the relevance of individual photoallergens changes over time. Currently, there is no evidence that PA reactions represent a common clinical problem.

A retrospective analysis of contact allergy to lanolin.

BACKGROUND: Lanolin is often stated to be an important sensitizer but some of the available literature is based on the analysis of high-risk patients. OBJECTIVES: To analyse the frequency of contact allergy to lanolin (wool alcohols) in a central London teaching hospital patch-test population. METHODS: Review of 24,449 patients recorded on our database during 1982--96 who were tested with a standard series containing 30% wool alcohols. RESULTS: 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. CONCLUSIONS: 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).

Changing frequency of thiuram allergy in healthcare workers with hand dermatitis.

BACKGROUND: Healthcare workers (clinical, allied/paramedical professions and ancillary workers) may have prolonged contact with natural rubber latex devices, particularly in the form of natural rubber latex gloves. OBJECTIVES: To examine the changing frequency of type IV thiuram allergy in healthcare workers with hand dermatitis over a 16-year period. METHODS: During the study period, 450 healthcare workers (352 women and 98 men) with hand dermatitis were investigated, and their patch test results were analysed retrospectively. RESULTS: On average, a thiuram-positive patch test was noted in 12% of individuals, with a peak incidence of 27% of the patients patch tested in 1994. Comparison of results between 1983--88 and 1989--93 showed a statistically significant increase in the incidence of thiuram-positive patch tests (odds ratio 2.55, 95% confidence interval 1.25--5.20, P = 0.01). CONCLUSIONS: We have documented a changing frequency of thiuram-positive patch tests in healthcare workers with hand dermatitis since 1983. This may reflect changes in degree of exposure to thiurams in medical gloves during this period.