Patch and photopatch test studies in 23 patients with reactions to
sunscreen preparations revealed 17 photopatch and 38 patch test-positive reactions. The offending
allergens could be traced in 18 of the 23 patients.
Allergy to
PABA was demonstrated in 11 patients, 5 of whom had photocontact
allergy. Photocontact
allergy to
oxybenzone was seen in 3 patients, while 8 were sensitive to
cinnamates, and 2 of these had a photocontact
allergy. Six patients were sensitive to the
PABA-derivatives octyldimethyl-
PABA and amyldimethyl-
PABA and the
ester glyceryl PABA, 2 of whom had a photocontact
allergy. None of the 3 patients with
benzocaine sensitivity, including 2 with a photocontact
allergy, reacted to the
PABA-
ester. Eight patients were sensitive to different
cinnamates, including 2 cases of photocontact
allergy. In one patient sensitivity to two azo-
naphthol dyes, contained in a
sunscreen preparation, was confirmed. Five other patients had positive skin test reactions to different
sunscreen preparations but the offending
allergen could not be traced. Thirteen of the 23 patients had chronic light sensitive disorders such as polymorphic light eruption (PMLE) or persistent light reactivity (PLR).
Sunscreen sensitivity appears to be more common than previously reported.