Prevalence of botanical extract allergy in patients with contact dermatitis.
BACKGROUND
Botanical extracts are used widely in over-the-counter products. They are primarily added for fragrance and their purported healing properties. Numerous case reports of allergic contact allergy to botanical extracts have been published; however, little is known regarding the prevalence of allergic reactions to botanical extracts.


OBJECTIVE
To determine the prevalence of allergic patch-test reactions to a collection of botanical extracts in patients referred for patch testing.


METHODS
A total of 140 patients were patch-tested to a study tray containing 47 botanical extracts. Patients were divided into two groups: (1) a high-risk group consisting of 21 patients with a clinical diagnosis of contact allergy who were using botanical products and whose contact dermatitis was not fully explained by testing to standard allergens and (2) a control group consisting of 119 patients with no history of botanical extract use and who were being evaluated in a contact dermatitis clinic.


RESULTS
Ten of 21 patients (47.6%) in the high-risk group had at least one relevant botanical extract positive reaction. Only 4 patients (3.4%) in the control group had a relevant positive reaction. Four patients in the high-risk group had more than one relevant botanical reaction. Tea tree oil caused the most common relevant positive reaction.


CONCLUSIONS
Contact allergy to botanicals was common in this highly selected group of patients. Contact dermatitis patients who use botanical products and whose reactions are not fully explained by standard patch testing may benefit from more extensive patch testing to botanical extracts.
Oregon Health & Science University, Department of Dermatology, Portland, OR 97239-3098, USA. simpsone@ohsu.edu
Eric L
EL
Simpson
Sandra V
SV
Law
Frances J
FJ
Storrs
D000485:Allergens / Q000009:adverse effects*; D016022:Case-Control Studies; D003358:Cosmetics / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D009922:Oregon / Q000453:epidemiology; D010328:Patch Tests; D008517:Phytotherapy / Q000009:adverse effects; D010936:Plant Extracts / Q000009:adverse effects*; D010938:Plant Oils / Q000009:adverse effects; D010944:Plants / Q000009:adverse effects; D020947:Tea Tree Oil / Q000009:adverse effects
D000485:Allergens; D003358:Cosmetics; D010936:Plant Extracts; D010938:Plant Oils; D020947:Tea Tree Oil