Evaluation of Axillae Skin Thickness by High-Frequency Ultrasound

BACKGROUND High-frequency ultrasound has been utilized in dermatology to visualize superficial cutaneous structures. Axillae are often target of treatments for hair removal, for spot clearing, and for skin conditions such as hyperhidrosis, bromhidrosis, and hidradenitis. Detailed knowledge of armpit thickness can help improve existing therapies and increase their effectiveness. OBJECTIVE To describe the mean skin thickness of axillae, by further investigating possible correlations with variations in age, sex, and body mass index (BMI). MATERIALS AND METHODS Axillae were divided into 5 quadrants, 1 central and 4 peripherals. Skin has been assessed by ultrasonography, measuring the distance from epidermis surface to dermal depth, in millimeters, for each of the regions. RESULTS Thirty healthy patients participated, most of them were female ( n = 22; 73%), mean age 50 years (26–70 years). Most patients have maximum thickness in the center of axillae (87%). Average skin thickness in the central region was 3.1 ± 0.4 mm. There was significant difference between axillary thickness in central and peripheral regions ( p < .05). On the periphery, the mean thickness was smaller (1.8 mm) without significant variation between the squares. There was no significant variation of skin thickness by sex, age, and BMI. CONCLUSION This study shows a difference between thickness of axillae in the central region and in its periphery.