What affects skin pH in healthy dogs by age, sex, and body factors

Abstract

BACKGROUND: Physiological skin pH levels are well-documented in human medicine, and assessment of variations may be important in assessing the efficacy of wound healing. By contrast, physiological skin pH levels in dogs are sparsely described. HYPOTHESIS/OBJECTIVES: To determine the pH of intact skin in healthy dogs and to study the influence of different physiological factors on the pH level of canine skin. ANIMALS: Seventy-seven client-owned dogs of various breeds, age and sex. METHODS AND MATERIALS: A prospective study was designed and the pH of intact skin was measured at the concave surface of both pinnae, and in both axillary and inguinal regions. For each location, the colour and density of the hairs also was recorded. Each dog's rectal body temperature and body condition scores also were determined. RESULTS: The skin pH in dogs <12&#x2009;weeks of age was significantly lower (3.97-5.70) than in older dogs (4.40-8.18) (P&#x2009;<&#x2009;0.001). In dogs >12&#x2009;weeks of age, skin pH was significantly lower in the inguinal regions compared to the pinnae (P&#x2009;=&#x2009;0.008), and female dogs had a significantly lower skin pH in the inguinal regions than male dogs (P&#x2009;=&#x2009;0.043). Pinnae covered with light-coloured hair had a lower skin pH than those with dark-coloured hair (P&#x2009;=&#x2009;0.04). No significant differences were found between dogs with different body condition scores, body temperatures or differences in hair density. CONCLUSIONS AND CLINICAL RELEVANCE: The pH of intact healthy skin is lower in puppies of <12&#x2009;weeks of age. Regional differences of body location also were seen which were variably affected by hair colour and sex. A baseline assessment of skin pH in healthy dogs is important for future studies of disease and wound healing.