Comparison of on-site and photographic evaluations of the suppressive effects of cetirizine, loratadine, and fexofenadine on skin response to histamine lontophoresis: A double-blind, crossover study in healthy volunteers

In this study in healthy volunteers, single doses of CTZ 5 mg and CTZ 10 mg were more potent compared with single-dose LOR 10 mg and FEX 60 mg BID in suppressing skin response. Although linear correlations were found between skin-response areas, as measured by on-site and photographic evaluation, it was difficult to differentiate between wheal and flare by photographic evaluation, especially when a typical wheal was suppressed to slightly edematous erythema by antihistamines.