A rash indicates an abnormal change in skin colour or texture.
Some skin rashes may be caused by a virus, such as chicken pox, shingles or measles.
Rashes are often caused by skin irritation, which can have many causes, such as an allergic reaction, or sting from a plant such as a stinging nettle.
Some rashes can be a sign of a serious condition, which in some cases may be life-threatening.
Some rashes are caused by chronic or lifelong conditions, such as psoriasis.
Here are some common types of rash:
Eczema is a general term that describes several conditions in which skin is inflamed, red, dry, and itchy. Eczema is a common skin condition, and atopic dermatitis (also called atopic eczema) is one of the most common forms of eczema.
Eczema can occur in adults or children. The condition is not contagious.
Granuloma annulare is a chronic skin condition that consists of a circular-shaped rash with reddish bumps (papules).
The condition mainly affects children and young adults who are otherwise healthy and is twice as common in women than in men.
Lichen planus is a common skin disorder that produces shiny, flat-topped bumps that often have an angular shape and a reddish-purplish colour. Lichen planus can occur anywhere on the skin but is often found on the insides of the wrists and ankles, the lower legs, the back, and the neck. Some people have lichen planus inside their mouth, genital region, hair and nails. Thick collections of bumps may occur, especially on the shins.
Lichen planus occurs most often in adults aged 30 to 70. It is not common in very young or elderly people.
Pityriasis rosea is a common, usually mild, skin rash that often begins with a large, scaly, pink patch of skin on the chest or back. The patch is usually followed by additional pink patches of skin. There is an itching of skin lesions and redness or inflammation of the skin. The number and sizes of the spots can vary.
Treatment for a rash will depend on what has caused it, such as an allergic reaction or virus.
Some home care may be possible with over-the-counter creams. However, if you have concerns seek medical advice.
If you are phoning for medical advice, for example on an NHS advice line, be prepared to describe the rash, when it developed and possible triggers.