Non-fluorinated topical corticosteroids give rise to a higher prevalence of contact allergy than fluorinated preparations, according to Dr K. F. Thomson (department of dermatology, Leeds General infirmary) and colleagues.
In a report to the British Journal of Dermatology (1999;141:863), they describe how they assessed skin patch test data for two populations of patients - one in Oxfordshire and the other in Greater Manchester - and calculated the prevalence of allergy to topical corticosteroids in both groups. In addition, they sent a questionnaire to consultant dermatologists in each area asking for details of their prescribing of topical corticosteroids to determine whether this had an effect on the prevalence of the allergy. Corresponding prescribing levels in general practice were obtained from the Prescription Pricing Authority and it was found that they reflected that of consultant dermatologists in both areas. A total of 1,451 Oxfordshire and 1,549 Manchester patients had been tested. In Oxfordshire, the prevalence of steroid allergy was 1.9 per cent while the corresponding figure for Manchester was 4.9 per cent.
The authors comment that there were regional variations within the Manchester group, as the overall allergy rate for Stockport was 3.8 per cent, while that for Wigan/Bolton was 8.3 per cent. The highest rate of prescribing of fluorinated corticosteroids (eg, betamethasone, clobetasone and fluticasone) was in Oxfordshire and the lowest was in Wigan/Bolton. The authors conclude that geographical differences exist in the prevalence of allergic contact dermatitis to topical corticosteroids and that the rate of allergy reflects the relative usage of non-fluorinated (eg, hydrocortisone) and fluorinated topical corticosteroids.