title: Chemical atopy.
abstract: BACKGROUND
  Although atopic disease is associated with protein allergy, its relationship with chemicals (haptens/contact allergens and irritants) is less clearly defined. The 'hapten-atopy' hypothesis, whereby significant hapten and irritant exposure during times of natural T helper (Th)2 bias (pregnancy and first year of life) promotes the development of atopy and atopic disease in the resulting child, has been previously proposed. Supporting evidence includes the practice of repeated cutaneous application of haptens in generating animal models of atopic dermatitis, and the observation of a significant increase in atopic disease in children born to mothers with occupations associated with high chemical exposure during pregnancy.
  
  
  OBJECTIVE
  To observe the relationship between personal chemical exposure and atopic disease in a particular case series.
  
  
  METHODS
  We report a case series of exacerbation of atopic dermatitis after repeated cutaneous chemical exposure.
  
  
  RESULTS
  Most of the patients had atopic dermatitis in young childhood that had resolved. However, after repeated chemical exposure, either occupationally as an adult or after starting to use cosmetics as a teenager, there was clear exacerbation of atopic dermatitis. Patch tests gave negative results in most cases.
  
  
  CONCLUSIONS
  We propose that repeated exposure to chemicals in patients with an atopic background can occasionally lead to reactivation of atopic dermatitis.
authors.affiliation: Department of Cutaneous Allergy, St. John's Institute of Dermatology, St. Thomas' Hospital, London, SE1 7EH, UK. pailin.samutrapong@gmail.com
authors.forename: Pailin
authors.initials: P
authors.lastname: Puangpet
authors.forename: Joey
authors.initials: J
authors.lastname: Lai-Cheong
authors.forename: John P
authors.initials: JP
authors.lastname: McFadden
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000009:adverse effects*; D003358:Cosmetics / Q000009:adverse effects; D003876:Dermatitis, Atopic / Q000453:epidemiology / Q000276:immunology* / Q000503:physiopathology; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology* / Q000503:physiopathology; D006241:Haptens / Q000009:adverse effects*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology / Q000503:physiopathology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects; D010328:Patch Tests; D011247:Pregnancy; D011379:Prognosis; D012008:Recurrence; D018570:Risk Assessment; D012494:Sampling Studies; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D000485:Allergens; D003358:Cosmetics; D006241:Haptens