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Regional variation of nonimmunologic contact urticaria. Functional map of the human face
1Department of Dermatology, School of Medicine, University of California, San Francisco 94143-0989, USA.
Background And Design:
Benzoic acid (BA) was used to induce nonimmunologic contact irritation in 10 younger (23-47 years old) and 5 older (72-90 years old) healthy volunteers. BA 2.5% in petrolatum was applied to 8 locations on the face, neck and volar forearm. Changes in the skin blood flow were monitored using a laser Doppler flowmeter. Also measured at each location were baseline measurements of skin blood flow, transepidermal water loss, stratum corneum hydration, skin surface temperature and skin surface pH.
Results:
The neck area exhibited the greatest reaction in both age groups while the forearm exhibited the least. At each site tested, the younger group consistently demonstrated greater reactivity to BA. A significant correlation was noted between stratum corneum hydration and irritation.
Conclusions:
This information provides a basis to further study the frequent poorly understood intolerance of the face to topical formulation.