Background
Obesity, defined as a body mass index (BMI) ≥30 kg/m2, affects up to 30% of UK adults.1 Its dermatological consequences are well established,1–3 but potentially under-appreciated in general practice. Examination may be hindered by larger skin folds and reduced visibility, while psychosocial barriers such as body image concerns may delay presentation. When patients do seek care, GPs have an opportunity to address both the skin condition and broader weight-related health. Understanding how obesity contributes to skin disease and the distinct management needs of this population is essential to improving outcomes in primary care.
How do obesity-related mechanisms cause changes in the skin?
Friction and moisture in skin folds
Obesity is associated with extensive skin folds in the axillary, neck, submammary, abdominal, and inguinal regions.4 Subcutaneous fat impairs thermoregulation, promoting sweating, friction, and moisture retention.1,4,5 This humid microenvironment predisposes to intertrigo and secondary infections, especially in those with diabetes or reduced mobility.1,4 The skin surface pH in obesity tends to be more alkaline than in normal-weight individuals, favouring fungal colonisation by Candida albicans.2 Erythrasma, caused by Corynebacterium minutissimum, is another common skin fold infection.2,3
Mechanical and pressure-related changes
In obesity, dermal elastic fibres stretch to accommodate expanding adipose tissue, leading to striae distensae (stretch marks) in areas of rapid or excessive weight gain.3,5,6 Abnormal gait mechanics and increased heel load elevate plantar pressures, causing physiological skin thickening.2,3 This manifests as plantar hyperkeratosis, a recognised marker of severe obesity.2,3,6
Vascular and lymphatic compromise
A higher BMI raises intra-abdominal pressure, impairing …
