Common rashes and their causes

Common Rashes and Their Causes

A rash is identified by a change in skin colour or texture and is usually itchy and red in colour, a rash can be present anywhere on the body. There are many different types of rash, all with different symptoms, and are usually easily treated. Here, we’ve rounded up the most common rashes and identified their causes.

Atopic Eczema

What is Atopic Eczema?

Atopic eczema, or atopic dermatitis, is the most common form of eczema it affects one in five children and one in twelve adults in the UK.

The symptoms of atopic eczema can be found on the surface of the skin. In mild cases the affected area becomes itchy, red, dry and cracked, the condition may affect small patches or may be spread all over the body.Common rashes: atopic eczema, HMT Hospitals

Atopic eczema is often found on the hands, insides of elbows, backs of knees, face and scalp, but can affect any part of the body. The severity of the condition varies from person to person and can be exacerbated by itching. Symptoms can be eased with emollients (moisturisers), steroid creams or antihistamines.


There is no one cause for atopic eczema, there is likely to be a combination of factors that contribute to the condition. Often, the people affected have very dry skin, which makes it more likely to react to certain triggers that could make the skin dry and itchy.

Common eczema triggers include :

  • Irritants
  • Allergens
  • Food allergies
  • Clothing materials
  • Hormonal changes
  • Skin infections

It is also likely for atopic eczema to be passed on through genes from parent to child. If one or both parents have eczema, the condition is likely to be passed on to the child.

We have a full guide to eczema.

Granuloma annulare

What is granuloma annulare?

Granuloma annulare is a rash that presents itself as a small ring of bumps, it commonly occurs on hands, feet, elbows or ankles. There are three main types of granuloma annulare: localised, widespread and under the skin.

Localised granuloma annulare is concentrated to just one or two areas, pink, purple or skin coloured patches appear and form a ring that slowly grows in size. The skin feels smooth and firm in this type of rash and the condition usually clears up on its own within a few months, fading back to a normal colour and texture.

Widespread granuloma annulare is rarer and usually affects adults, the symptoms are similar to the localised version but on a bigger scale, covering a larger portion of the body.

Under the skin granuloma annulare is when the spots develop under the layers of skin, the lumps feel firm and rubbery to the touch. Under the skin granuloma annulare is usually found in children.

The condition is difficult to treat, but the rash will disappear on its own within a few months to two years.  In severe cases, steroid creams, cryotherapy (freezing the spots), or ultraviolet light treatment can be used to help.


The bumps or spots occur when the tissue beneath the top layer of skin becomes inflamed and hypersensitive. There is no clear reason as to why this happens, but the condition is harmless and does not affect overall health.

Pityriasis rosea

What is pityriasis rosea?

Pityriasis rosea is a skin condition that causes a temporary rash that lasts two to twelve weeks, the rash usually appears as raised, red scaly patches on the body. The condition usually begins with a ‘herald patch’ – a single pink or red patch of scaly skin that appears on the chest, back or stomach about 5-15 days before the full rash develops.Common rashes: pityriasis rosea, HMT Hospitals

The rash usually goes away without any treatment within 12 weeks, although it has been known to last up to five months. Emollients (moisturisers), steroid creams and antihistamines can be used to help ease the itching.


Although the exact cause of pityriasis rosea is not known, research suggests that the condition may be the result of a viral infection due to the rash’s resemblance to other viral illnesses.

Pityriasis rosea is not contagious so cannot be spread by physical contact.


What is urticaria?

Urticaria, sometimes referred to as hives, is a raised, itchy rash that can occur anywhere on the body. The rash is usually extremely itchy and can cause discomfort to the person affected. Urticaria often settles with no treatment within a few days, with improvement in symptoms occurring within 24 hours.Common rashes: urticaria, HMT Hospitals

Acute urticaria describes the condition when the rash goes away within six weeks, and chronic urticaria is when the rash persists for more than six weeks, often over months or years. Visit your doctor if the symptoms do not go away within 48 hours.

Treatment is not always needed for urticaria as the rash and symptoms are usually mild and get better within a few days, in severe cases antihistamines can be used to block the histamine that causes the itchiness and rash, or corticosteroid tablets which suppress the immune system, lessening the symptoms.


Urticaria flares up when the skin is exposed to a trigger that causes high levels of histamine and other chemicals to be released. These chemicals cause blood vessels to open up and leak, which causes the red or pink colour in the rash and causes the tissue to swell up thanks to the extra fluid.

These triggers can be a variety of things and vary from person to person, it could be a food allergy, allergic reaction, stress, infection, medications. In chronic urticaria, around a third of all cases are thought to be an autoimmune reaction, where the body attacks its own tissues.


What is impetigo?

Impetigo is a skin condition that presents itself in the form of sores and blisters, it is the most common skin infection in young children in the UK and is highly contagious. There are two main types of impetigo: non-bullous and bullous.

Non-bullous impetigo begins as red sores, usually around the mouth or nose, that burst quickly and scab in the affected area, during the healing process they leave a red mark that does not scar. The symptoms can disappear completely within a few days or weeks.

The first symptom of bullous impetigo is the appearance of fluid-filled blisters on the waist, neck, arms or legs, these blisters tend to spread quickly and will burst after several days.

Treatment is often recommended to help clear the infection and prevent the spread, antibiotics are the most effective treatment and can be prescribed in cream or tablet form.


This type of rash occurs when bacteria infects the skin, either through a break in healthy skin, such as a cut or insect bite or through skin that has been damaged by another underlying condition such as eczema. As impetigo is highly contagious, physical contact with someone who has the infection, or other close contact, can spread the infection easily. The symptoms do not show themselves until four to ten days after initial exposure, so unintentional spreading is easily done.


What is psoriasis?

Psoriasis is an autoimmune skin disease, the rash like symptoms are long lasting and cause the skin to go red and flaky, often resulting in silvery scales covering the affected area.Common rashes: psoriasis, HMT Hospitals

Psoriasis affects around 2% of the UK population and can start at any age, the severity varies from person to person and can range from a minor irritation to a major impact on daily life.

The condition is not contagious and while there is no cure, it can be treated with topical treatments or phototherapy.


The body is constantly producing new skin cells in the deepest layer of skin, these new skin cells move towards the outer layer and when they reach the outermost layer they die and flake off, this is happening constantly and usually takes three to four weeks.

When someone is suffering from psoriasis, this process is sped up and only takes three to seven days, meaning that skin cells that aren’t ready to flake off build-up on the surface of the skin, creating the red, flaky patches.

Research suggests that this cause is related to a problem with a person’s immune system, because of the over-production, the body’s defence attacks healthy skin cells.

There are also genetic factors at play, as psoriasis is known to run in families, but the condition is not a straightforward genetic disease, with complications stemming from environmental factors and the suggestion that more than one gene is responsible for the development of psoriasis.

Read our complete guide to psoriasis.


What is ringworm?

Ringworm is a fungal infection that can affect anywhere on the body, it causes a red or silvery ring-like rash and most commonly occurs on the arms and legs. Ringworm is part of a larger family of fungal infections knows as ‘tinea’, these are not serious but are contagious and easily spread. The affected area tends to be scaly, inflamed and itchy.Common rashes: ringworm, HMT Hospitals

People of all ages can get ringworm and it is estimated that 10-20% will experience it in their lifetime, the condition can be treated with antifungal creams from the pharmacy and does not require a visit to the doctor unless the symptoms persist.


Ringworm, and other tinea fungal infections, is caused by a type of fungi called dermatophytes. Dermatophytes live off keratin, which is a waterproof tissue that is found in the skin, hair and nails.

The fungi are tiny spores that thrive in heat and moisture and can survive for months in that environment. The spores can be spread in four main ways: human-to-human contact, human-to-animal contact, human-to-object or human-to-soil.


If you have an unexplained rash, or symptoms that persist for more than 48 hours, visit your doctor for a diagnosis. There are many common rashes and getting the right diagnosis is the first step towards treatment.

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St Hughs in Grimsby – 01472 251 100

Sancta Maria in Swansea – 01792 479 040