A rash is defined as a change in the skin’s appearance, which may involve alternations in texture (eg rough or smooth) and/or colour. The skin may also become itchy, warmer, dry, cracked, blistered, lumpy or painful. Depending on where the rash is located, other symptoms you are experiencing, what you have been exposed to and any family history, there are many causes for a rash.

It is therefore very important to be aware of where the rash initially arises from, how it changes or spreads and recognize symptoms and signs that suggest that you should seek medical attention immediately. These details and other important issues such as common causes, associated medical conditions and basic management of rashes will be discussed below.

Rashes can be divided into acute (short term) and chronic (longer term) causes. Within the acute group, they can be blanching (disappearing when pressed) or non-blanching. In the chronic group, it is useful to divide them into itchy and non-itchy causes. There are also a number of medical conditions which can be associated with rashes.

Medical conditions associated with a skin rash
Erythema Nodosum
Erythema Nodosum is a skin condition where red, tender/painful lumps form on the shins, and less commonly the thighs and forearms. More commonly occurring in young females, the condition can be caused by many factors, including; bacterial infection, drugs (oral contraceptive pill, aspirin), or inflammatory bowel disease

Erythema Multiforme
This skin rash usually appears suddenly, after exposure to the causative agent. Although the cause is unknown in about 50%, possible causes include: herpes simplex virus, other viral infections, drugs (anti-epileptic drugs), connective tissue diseases (systemic lupus erythematosus) and HIV infection.

Dermatomyostitis
Dermatomyositis: inflammed skin and muscle which may occur in childhood or adult life. It usually presents with distinctive facial redness, a purple coloured skin rash around the eyes and swelling. The knuckles and arms and legs may develop blue/red nodules or patches. If you are affected by dermatomyositis you may feel some muscle discomfort and weakness.

Scleroderma
Scleroderma refers to a group of diseases in which there are changes in the layers of the skin, producing thickened layers, and destruction of hair follicles and sweat glands. The lungs, bowels, kidneys and heart may all be affected. Skin may become tight and tethered, especially around the hands, mouth and nose.