Patch testing in a British district general hospital

Epidemiological data on consumer allergy to p-phenylenediamine

Many women and men now dye their hair. p-Phenylenediamine (PPD) is a frequent and important component of permanent hair dye products; exposure to it may cause allergic contact sensitization, acute dermatitis, and severe facial oedema. To increase our understanding of PPD allergy, we reviewed published literature containing PPD patch test data from dermatitis patients and individuals in the general population. This was performed to estimate the median prevalence and the weighted average of PPD sensitization and thereby assess the burden of PPD-containing hair care products on health. Literature was examined using PubMed-MEDLINE, Biosis, and Science Citation Index. The median prevalence among dermatitis patients was 4.3% in Asia, 4% in Europe, and 6.2% in North America. A widespread increase in the prevalence of PPD sensitization was observed among Asian dermatitis patients. In Europe, a decrease in the 1970s was replaced by a plateau with steady, high prevalences ranging between 2% and 6%. The prevalence remained high in North America, although a decreasing tendency was observed. Contact allergy to PPD is an important health issue for both women and men. More stringent regulation and enforcement are required as public health measures to reduce the burden of disease that exposure to PPD has brought to populations.

Common contact sensitizers in the Czech Republic. Patch test results in 12,058 patients with suspected contact dermatitis*

The patch test results of 12 058 patients (4416 male and 7642 female) referred to 9 clinics in the Czech Republic between January 1997 and December 2001 were evaluated. Patients were tested with the same series of allergens by using the standardized patch testing method. The current standard tool for diagnosing allergic contact dermatitis (ACD) in the Czech Republic is the Trolab test panel (Hermal, Reinbeck, Germany) which consists of 23 allergens. Only a few data exists on ACD in the Czech Republic. All patients were tested with the 23 allergen European standard series. Of these patients, 7661 (63.5%) had 1 or more positive reactions. On average, there were 2.8 positive reactions per patient. ACD, according to clinical relevance, was diagnosed in 5339 (69.7%) of these patients. The most frequent allergens were metals (22.9%), especially nickel sulfate (13.8%), and followed by Myroxylon pereirae resin (balsam of Peru) (7.3%), fragrance mix (5.8%), formaldehyde (4.2%) and lanolin alcohol (3.0%). Our results were compared with results from other countries. We conclude that the European standard series is suitable for detection of ACD in the Czech Republic.

The importance of a dedicated patch test clinic

BACKGROUND

A specialist patch test clinic was set up in April 1997 at the Department of Dermatology, South Infirmary-Victoria Hospital, Cork, Ireland. The number of batteries available was expanded from six to 21 and the routine testing of patients to their own products was introduced, as was prick testing for latex hypersensitivity.

OBJECTIVES

To assess the impact of introducing this clinic on the detection of allergic contact dermatitis.

METHODS

Patch test results for the first full year of operation of the clinic (1998) were compared with those in the year prior to setting it up (1996).

RESULTS

Although the number of patients tested rose after the introduction of the new clinic, the difference was not significant as the number of new dermatology general referrals had also risen. Thirty-one of the 91 patients tested in 1996 had positive patch tests compared with 84 of 158 tested in 1998 (P = 0.0036). Eighteen allergens were detected in 1996 and 53 in 1998. Two patients were positive to their own products in 1996, compared with 12 in 1998 (P = 0.04). The commercial batteries were negative in four of these cases. Three cases of latex hypersensitivity were detected in 1998.

CONCLUSIONS

The introduction of a specialist patch test clinic resulted in an increase in detected cases of allergic contact dermatitis. The larger range of batteries available and the more widespread testing of patients' own products were the principal factors involved.