Intertrigo (Sweat Rash): Symptoms, Causes and Treatment in the UK

Intertrigo is the medical term for a rash that develops in the folds of the skin. It is primarily caused by skin-to-skin friction, which is worsened by heat and trapped moisture. In the UK, it is often colloquially referred to as a 'sweat rash'. While it can affect anyone, it is more prevalent among individuals with diabetes, those who are overweight, or those who live in humid environments.

According to NHS guidance, intertrigo occurs most frequently in areas where skin surfaces rub together. These areas are naturally warmer and more prone to perspiration, creating an ideal environment for the skin barrier to break down. Once the skin is macerated (softened by moisture), it becomes highly susceptible to secondary infections from fungi (yeasts) or bacteria.

The symptoms of intertrigo usually begin as mild redness or a pinkish tint in a skin fold. Over time, if the irritation continues, the skin may become itchy, sore, or raw. In more severe cases, the skin may crack, peel, or even bleed.

Commonly affected areas include:

• Under the breasts: A frequent site for women, particularly if wearing ill-fitting bras.
• The groin and inner thighs: Often aggravated by walking or exercise.
• The armpits: Where sweat and deodorant can cause further irritation.
• The abdomen: Specifically under skin folds or 'aprons'.
• Between the toes or buttocks: Other narrow areas where airflow is limited.

If the rash develops a foul smell, yellowish crusting, or small 'satellite' spots (tiny red bumps nearby), this often indicates a secondary yeast or bacterial infection.

The primary cause is the mechanical friction of skin rubbing against skin. This friction causes inflammation. However, the dark, warm, and moist environment of a skin fold is a breeding ground for microorganisms. NICE (National Institute for Health and Care Excellence) notes that Candida albicans (the yeast responsible for thrush) is the most common secondary invader in intertrigo cases.

Other contributing factors include hyperhidrosis (excessive sweating), poor hygiene, and the use of tight-fitting, non-breathable clothing made from synthetic fabrics. For those with compromised immune systems or poorly managed diabetes, the risk of the rash progressing into a deeper infection like cellulitis is significantly higher.

Treatment for intertrigo focuses on two goals: reducing inflammation and eliminating any underlying infection. Simple, uninfected intertrigo may respond well to lifestyle changes and barrier creams, such as zinc oxide or petroleum jelly, which protect the skin from further friction.

Prescription and Over-the-Counter Treatments

• Antifungal Creams: If a yeast infection is suspected, treatments containing clotrimazole or miconazole are often recommended.
• Mild Steroid Creams: A short course of 1% hydrocortisone cream may be prescribed to reduce redness and itching.
• Combined Treatments: In many cases, a GP may prescribe a cream that combines both an antifungal and a mild steroid (such as Daktacort) to treat the infection and the inflammation simultaneously.
• Antibiotics: If a bacterial infection is confirmed (often indicated by pus or crusting), a topical or oral antibiotic may be required.

Prevention is a key component of managing skin fold rashes. The goal is to keep the skin dry and reduce friction. UK health professionals recommend the following steps:

• Dry thoroughly: After showering, ensure skin folds are gently patted dry. Some people find using a hairdryer on a 'cool' setting helpful for hard-to-reach areas.
• Wear breathable fabrics: Choose cotton underwear and loose-fitting clothing rather than synthetic materials like polyester or nylon.
• Use anti-chafing products: Barrier balms or specialised powders can help reduce friction during physical activity.
• Weight management: Reducing skin-to-skin contact through weight loss can often provide long-term resolution for recurrent intertrigo.
• Blood sugar control: If you are diabetic, maintaining stable blood glucose levels helps the skin resist fungal infections.

Many mild cases of sweat rash can be managed at home. However, you should seek medical advice if the rash does not improve after five to seven days of self-care. If you are unsure whether the rash is intertrigo, psoriasis, or another skin condition, a professional diagnosis is essential.

You can speak to a GP online to show them the affected area via a secure video consultation or by uploading clear photos. This allows for a quick assessment and, if necessary, a prescription for medicated creams to be sent to your local pharmacy. Seeking treatment early prevents the rash from becoming a more painful, spreading infection.