Evaluation of photopatch test allergens for Indian patients of photodermatitis: preliminary results.

BACKGROUND: There is a strong need to develop a photopatch test tray suitable for Indian patients of photodermatitis as European/Scandinavian photopatch test trays may not be wholly relevant for them. AIM: We carried out this study using photoallergens relevant in the Indian context to determine their relevance in patients of photodermatitis. METHODS: Thirty patients (M:F, 23:7) between 19 and 76 years of age of photodermatitis and 10 controls were patch- and photopatch tested with 20 common photoallergens. In addition, the patients were also (photo) patch tested with articles of daily use as and when these were suspected to be the cause. RESULTS: Forty-three positive reactions to one or more antigens were seen in 22 (74%) patients. Fourteen positive photopatch tests to seven allergens were observed in 10 (33%) patients, and nine (30%) of them had a definite relevance. The most common contact allergen was fragrance mix (FM) (30%), followed by p-phenylenediamine (20%) and Parthenium hysterophorous (17%). The definite relevance of the patch- and photopatch tests could be correlated in 47% of these patients. CONCLUSIONS: FM is the most common contact and photocontact allergen among the various photopatch test antigens. Although differences in technique and evaluation make direct comparison between different centers difficult, still photopatch testing remains an integral part and gold standard for the work-up of the photosensitive patients.

Occurrence of plant sensitivity among patients of photodermatoses: a control-matched study of 156 cases from New Delhi.

BACKGROUND: Photodermatitis is an abnormal response to ultraviolet radiation (UVR). The photoallergic contact dermatitis caused by plant allergens is a serious cause of morbidity in India. Airborne contact dermatitis is the classical presentation of plant-induced dermatosis, which may become difficult to differentiate from chronic actinic dermatitis in chronic cases. The rapid growth of parthenium weed in India and its ill effects on the population make it important to detect all cases of parthenium sensitivity, which in some cases might simulate photodermatitis. AIMS: This study aims to detect the occurrence of plant sensitivity and photosensitivity in idiopathic-acquired photodermatoses, airborne contact dermatitis and general population taken as controls. METHODS: One hundred and fifty six consecutive patients suffering from polymorphic light eruption (PMLE), chronic actinic dermatitis (CAD) and airborne contact dermatitis (ABCD) were enrolled in the study over a period of three years (June 2004 to May 2007). An equal number of age and sex matched healthy subjects were enrolled in the study as controls. All the patients were subjected to detailed history taking, clinical examination and histopathological examination for diagnosis. Patch and photopatch testing were perfomed in all the patients and healthy controls for detection of allergic and photoallergic reactions to parthenium, xanthium and chrysanthemum plant antigens and control antigens. RESULTS: Out of 156 patients enrolled in the study, 78 (50%) had CAD, 67 (42.9%) had PMLE and 11 (7.05%) had ABCD. The occurrence of parthenium/xanthium allergy and photoallergy, either to parthenium or both was most commonly found in ABCD (72.7%), followed by CAD (32%). In PMLE 4.5% cases showed photoallergy. Only 1.9% in the control group showed sensitivity to parthenium and xanthium. CONCLUSION: This study indicates that parthenium (and possibly xanthium) may act as important environmental factors in the initiation and perpetuation of not only ABCD but of CAD as well. Photoexacerbation to UVA at positive parthenium/xanthium sensitivity sites in ABCD and CAD indicates that ABCD with photosensitivity to compositae can lead to CAD.