title: Occurrence of plant sensitivity among patients of photodermatoses: a control-matched study of 156 cases from New Delhi.
abstract: 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.
  
  
  OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Dermatology, Dr. Ram Manohar Lohia Hospital, New Delhi, India. hkkar_2000@yahoo.com
authors.forename: Hemanta Kumar
authors.initials: HK
authors.lastname: Kar
authors.forename: Sonali
authors.initials: S
authors.lastname: Langar
authors.forename: Tarlok Chand
authors.initials: TC
authors.lastname: Arora
authors.forename: Pankaj
authors.initials: P
authors.lastname: Sharma
authors.forename: Alok
authors.initials: A
authors.lastname: Raina
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Bhardwaj
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D052179:Antigens, Plant / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology; D017454:Dermatitis, Photoallergic / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010787:Photosensitivity Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology; D010944:Plants / Q000009:adverse effects / Q000276:immunology; D014466:Ultraviolet Rays / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D052179:Antigens, Plant