Ringworm vs eczema: telling a fungal rash from an eczema patch

Ringworm and eczema can both produce a red or discoloured, scaly, itchy patch, and some eczema patches are round. The important differences are the cause and the consequences. Ringworm is a fungal infection that is catching: if you scratch it you can spread it, and you can pick it up from people, pets and shared towels. Eczema is a skin condition driven by the skin barrier and immune system. It is not infectious and tends to come back in the same areas.

Because the treatments are different, it is worth getting the rash looked at rather than reaching for whatever cream is in the cupboard. The NHS advises speaking to a pharmacist first if you think you have ringworm, as they can look at the rash and recommend antifungal medicine, and advises a GP appointment if it has not improved with treatment.

The NHS describes ringworm as a common fungal infection whose main symptom is a rash. The rash may look red or darker than the surrounding skin, depending on skin tone, and may be scaly, dry, swollen or itchy. It is usually ring-shaped but may look different on the face, neck or scalp, can grow or spread, or there may be more than one rash. On the face or scalp it may cause patchy hair loss. It can appear anywhere, including the scalp (tinea capitis) and groin (jock itch), and the colour may be less noticeable on brown and black skin.

It spreads through close contact with an infected person or animal, infected objects such as bedsheets, combs or towels, and less commonly soil. The NHS advises starting treatment as soon as possible, washing towels and bedsheets regularly, not sharing towels or combs, not scratching the rash, and taking a pet to the vet if it has patches of missing fur. It is fine for a child to go to school or nursery once treatment has begun.

Discoid eczema, also called nummular or discoid dermatitis, causes distinctive circular or oval patches of eczema, according to the NHS. It usually starts as a group of small spots or bumps that join into larger patches, which may be swollen, blistered and oozing at first, and very itchy, particularly at night. Over time they can become dry, crusty, cracked and flaky. It does not usually affect the face or scalp, and the NHS says the centre of a patch sometimes clears, leaving a ring of discoloured skin that can be mistaken for ringworm. It is long term and may keep coming back in the same area.

Atopic eczema, the more common form, is dry and itchy skin that is common on the elbows, knees and hands, and it usually starts in babies and young children. The British Association of Dermatologists says it may also appear as coin-sized areas of inflammation (a discoid pattern) or in the creases of joints. A healthcare professional can usually recognise atopic eczema by looking at the skin, and tests are usually unnecessary.

Several clues point towards ringworm: a rash that is expanding and has appeared recently, a pet with missing fur or someone at home with a similar rash, shared towels or sports equipment, and a rash on the scalp with hair loss. Several point towards eczema: a long history of dry, itchy skin, a family history of eczema, asthma or hay fever, rashes that recur in the same places, and multiple patches that are very itchy at night.

The reason to be careful is that the two are treated differently. The NHS says ringworm usually needs an antifungal used for the right length of time, up to 4 weeks, even when the rash seems to have gone, and that scalp ringworm needs prescription tablets and shampoo. The NHS says a pharmacist can look at the rash and recommend the best antifungal medicine, and will say if you should see a GP, while a healthcare professional can usually recognise atopic eczema by looking at the skin.

The NHS says to see a GP if ringworm has not improved after using the antifungal medicine a pharmacist recommended, if it is on the scalp, or if you have a weakened immune system. For atopic eczema, it says to ask for an urgent GP appointment or contact NHS 111 if the skin is blistered, crusty, leaking fluid, painful, swollen or warm, if it suddenly worsens, or if you have a high temperature or feel generally unwell, as these may be signs of infection. For discoid eczema it advises seeking medical advice if you think the skin may be infected.