Erythrasma

Overview

Erythrasma is a common skin condition that causes flat, brown or reddish-brown patches in the folds of your skin. It is caused by a type of bacteria (tiny germs) that normally live harmlessly on your skin. When the skin stays warm and damp, these bacteria grow more than usual and cause a rash. Erythrasma is not dangerous, it is not a sign of poor hygiene, and it usually clears up well with treatment.

Yes, erythrasma is fairly common. It is seen more often in warm, humid climates and in people who have larger skin folds.

Anyone can get it, but it is more common in adults than in children, in people who are overweight, in people with diabetes, and in people who live in hot, humid places. It also affects people who sweat a lot or wear tight clothing that traps moisture.

Symptoms

Common symptoms

• Flat, brown or reddish-brown patches in skin folds
• Mild scaling or a slightly crinkly look on the surface of the patch
• Little or no itching — many people feel nothing at all
• Occasional mild soreness or irritation in the affected area
• Patches that slowly get bigger over weeks or months
• A faint musty smell in some people

Symptoms in children

• Erythrasma is uncommon in young children
• When it does happen, it tends to appear between the toes or in the groin area
• Children may not notice it at all, so parents often spot it first

Symptoms in older adults

• More common in older adults, especially in people with diabetes
• Often found in deeper skin folds under the breasts or belly
• May be confused with other skin problems, so a check-up helps
• Skin can be more fragile, so gentle washing and drying is important

Causes

Main causes

• Overgrowth of a bacterium called Corynebacterium minutissimum, which normally lives on healthy skin
• Warm, moist skin folds where bacteria can multiply
• Sweating and trapped moisture under tight clothing

Risk factors

• Being overweight or having deeper skin folds
• Diabetes (high blood sugar can feed bacterial growth)
• Living in a hot, humid climate
• Sweating a lot (for example from exercise or hot weather)
• Wearing tight clothing or synthetic fabrics that trap moisture
• A weakened immune system
• Older age
• Having had erythrasma before

When to see a doctor

See a doctor urgently if:

• The area becomes very painful, hot, red, or starts to weep or smell strongly
• You have diabetes and the rash is getting worse or not healing
• You feel generally unwell with fever or chills
• The skin breaks down or forms an open sore

Book a routine appointment if:

• You have a brown or red patch in a skin fold that does not go away
• You are not sure whether it is erythrasma or a fungal infection
• The rash keeps coming back after treatment
• The rash is spreading or bothering you

Diagnosis

A doctor or nurse can often recognise erythrasma just by looking at the skin. Because it looks similar to fungal infections, they may use a simple lamp test or take a small skin sample to be sure.

Tests that may be done

• A Wood's lamp test — a special purple light that makes erythrasma glow a coral-red colour
• A small skin scraping looked at under a microscope or sent to a lab
• Sometimes a check for a fungal infection at the same time, to rule it out

What to expect at your appointment

The check-up is quick and painless. Your doctor will look at the area and may shine a light on it or gently scrape a tiny bit of skin. You usually get an answer the same day, and treatment can start straight away.

Treatment

Erythrasma is treated with medicines that kill or stop the growth of the bacteria. Most people clear up within a few weeks. Keeping the skin clean and dry helps treatment work and lowers the chance of it coming back.

Self-care at home

• Wash the area gently with mild soap and water, then dry it fully — pat rather than rub
• Wear loose cotton clothing and change out of sweaty clothes soon after exercise
• Use a separate towel for the affected area and wash towels often
• Avoid sharing towels with others
• Try to keep skin folds dry, especially in hot weather
• Do not scrub the patches or use harsh soaps or perfumed products

Medical treatments

Treatment usually involves an antibacterial cream, lotion or gel applied to the skin for a few weeks. If the rash covers a large area or keeps coming back, your doctor may suggest antibacterial tablets taken by mouth. Your doctor will choose the option that suits you, and it is important to finish the full course even if the skin looks better. Always ask your pharmacist or doctor before using any medicine, including over-the-counter creams, because fungal treatments do not work for erythrasma.

When is surgery considered?

Surgery is not used to treat erythrasma.

Living with this condition

Erythrasma usually causes little discomfort, so most people can carry on with normal life while it clears up. The main day-to-day task is keeping the skin folds clean and dry and using your treatment as directed.

Lifestyle tips

• Choose loose, breathable clothing, especially in warm weather
• Shower after exercise or heavy sweating and dry well
• Keep your blood sugar well managed if you have diabetes
• Use an absorbent powder if your doctor or pharmacist suggests one
• Check skin folds regularly so you notice changes early

Diet and exercise

There is no special diet for erythrasma. Eating a balanced diet and staying active are good for your general health, and if you have diabetes, keeping your blood sugar in range can reduce flare-ups. After exercise, shower and dry your skin folds to lower the chance of the bacteria growing.

Mental health and emotional wellbeing

Some people feel self-conscious about a rash in the armpits, groin or under the breasts. This is understandable. Erythrasma is not infectious in a day-to-day sense and is not caused by poor hygiene, so you do not need to feel embarrassed. If the condition is making you anxious or low, talk to your doctor — support is available.

Prevention

You cannot always prevent erythrasma, but keeping skin folds clean, cool and dry lowers the chance of it starting or returning.

Screening programmes

There is no screening programme for erythrasma. Because it is more common in people with diabetes, keeping up with your routine diabetes checks is a good idea.

Complications

If left untreated

• The patches may slowly get larger
• Itching or mild soreness may develop
• The skin may become cracked, which can let in other germs
• It may be mistaken for a fungal infection and treated with the wrong product
• In people with diabetes, skin problems can be slower to heal

Long-term outlook

The outlook is very good. Erythrasma clears up well with the right treatment, and most people see a big improvement within a few weeks. It can come back, particularly in warm weather or if the skin stays moist, but it can be treated again successfully. It is not a dangerous condition and does not affect your general health.

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