Experimental Candida albicans lesions in healthy humans: dependence on skin pH

Abstract

The addition of suspensions of Candida albicans cells under occlusion to the left and right forearms, buffered at 2 different pH levels (6.0 and 4.5), resulted after 24 h in unilateral or bilateral lesions in 14 of 15 volunteers. The resulting skin-surface pH was 5.7+/-0.3 and 5.1+/-0.2, respectively. The lesions were more pronounced on the arm with the higher pH in all 14 subjects who reacted. In 11 cases, reactions occurred only on the arm with the higher pH. The pH-induced results are not due to inhibited growth of C. albicans. They may be due to a pH dependence of the yeast's virulence capacity and/or a modulation of the host's defence ability. The use of skin-occlusive products (e.g. dressings, diapers and panty liners) is known to raise skin pH and is associated with skin infections of C. albicans. An acidic buffer incorporated in such products could be a preventive measure for Candida-induced skin rash.