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Compound tincture of benzoin: a common contact allergen?
Laura Scardamaglia1, Rosemary Nixon, John Fewings
1Contact Dermatitis Clinic, Skin and Cancer Foundation, Melbourne, Victoria, Australia.
Abstract:
The results of patch testing to compound tincture of benzoin in 477 patients performed at the Contact Dermatitis Clinic at the Skin and Cancer Foundation in Melbourne during 1999 are presented. There have been fewer than 30 reported cases of contact allergy from compound tincture of benzoin, and none in the last decade. Our results showed 45 out of the 477 patients had a positive reaction to compound tincture of benzoin, which was the third most common allergen in our series. Of these 45 patients, 14 had strong positive reactions, but only two definitely recalled exposure to compound tincture of benzoin and these were clinically relevant. Twenty-eight of these patients had cross-reactions to similar allergens (fragrance mix, balsam of Peru, colophony and tea tree oil). Of the 14 patients with a strong positive reaction to compound tincture of benzoin, 11 had at least one other positive cross-reaction to the above allergens. This may explain the high frequency of reaction to compound tincture of benzoin found in our study.
Insights
Compound tincture of benzoin caused allergic reactions in 45 of 477 patients, making it a common allergen. Many reactions were linked to cross-allergies with fragrances and natural resins.
Area of Science:
- Dermatology
- Allergology
- Contact Dermatitis
Background:
- Compound tincture of benzoin is used in dermatology, but reported cases of contact allergy are rare.
- Previous literature indicates fewer than 30 cases of allergy to compound tincture of benzoin, with none reported in the last decade.
Purpose of the Study:
- To present the results of patch testing with compound tincture of benzoin in a patient cohort.
- To investigate the frequency and potential causes of positive reactions to compound tincture of benzoin.
Main Methods:
- Patch testing was conducted on 477 patients at the Contact Dermatitis Clinic, Skin and Cancer Foundation, Melbourne.
- Patients were tested with compound tincture of benzoin, and reactions were recorded.
- Cross-reactions to fragrance mix, balsam of Peru, colophony, and tea tree oil were assessed.
Main Results:
- A significant number of patients (45/477) showed a positive reaction to compound tincture of benzoin, identifying it as the third most common allergen in the study.
- Fourteen patients had strong positive reactions; only two recalled relevant exposure.
- Twenty-eight patients exhibited cross-reactions to similar allergens, with 11 of 14 strongly reacting patients showing at least one cross-reaction.
Conclusions:
- Compound tincture of benzoin is a more frequent contact allergen than previously reported.
- Cross-reactivity with other allergens, particularly fragrances and natural resins, may contribute to the high observed frequency of reactions.
- Further investigation into cross-reactivity patterns is warranted to understand benzoin allergy.