Skin complaints such as rashes are relatively common problems among people with HIV.

Causes

There are many different kinds of rashes and specialist advice may be required to establish the cause.

A red blotchy generalised rash over the whole of the body starting soon or several days after starting a new medication suggests an allergy. The rash is usually accompanied by itching and sometimes fevers and if severe, mouth ulceration.

Many drugs can cause a rash and this appears to happen more frequently in people with HIV infection, especially if they have been diagnosed with AIDS. Nevirapine causes a rash in around 16% of people who start the drug. Antibiotics are also a frequent cause, particularly penicillins or co-trimoxazole.

A range of infections can cause skin irritations in people with HIV. Common causes are psoriasis, herpes simplex, herpes zoster (shingles) and Molluscum contagiosum.

Itchy skin or pruritus commonly occurs in advanced HIV disease. Dysregulation of the immune system may contribute to pruritus.

Skin eruptions that harden into nodules called prurigo or 'pruritic papular eruption' are common among HIV-infected people in sub-Saharan African. This condition results from insect bites which become highly inflamed due to disrupted immune function.

The sexually transmitted infection, syphilis, can cause have rash as one of its symptoms. Often this rash takes a blotchy brown character and affects the palms of the hands and soles of the feet.

What to do

If the rash seems to be linked to a drug, what to do will depend on the drug you are taking.

Nevirapine can cause a serious rash and about 7% of nevirapine recipients discontinue the drug due to rash. Dose escalation or antihistamines may reduce the risk of rash. If serious rash develops, the drug should be stopped immediately. See Nevirapine - overview in Drugs used by people with HIV: Non-nucleoside reverse transcriptase inhibitors for further information on what to do if a rash develops during the early weeks of nevirapine treatment.

If a rash, fever or malaise occurs in the early weeks of abacavir treatment, these symptoms should be reported to your doctor immediately. They may be signs of a serious allergic reaction called a hypersensitivity reaction. If this is diagnosed, abacavir should be stopped at once and should not be started again, because of the risk of a life threatening return of the allergic reaction. See Abacavir - overview in Drugs used by people with HIV for further information on this topic.

Rash has also been seen as a side effect of efavirenz and amprenavir, but with less serious effects than the drugs described above. Rash is also a frequent side effect of co-trimoxazole (Septrin). See Co-trimoxazole in Drugs used by people with HIV for details of dose escalation studies to reduce the risk of serious rash when starting treatment with this drug.

Rash is also a side effect of almost all the drugs used to treat tuberculosis.

In the case of less serious rash reactions to other drugs, anti-histamines such as Piriton or Zirtek may be of help. Check with your pharmacist if you plan to use antihistamines that you bought over the counter without a prescription - they can interact with some anti-HIV drugs.

If the allergic reaction is severe then you should seek urgent help from your doctor, as hospitalisation and urgent treatment may be necessary.

Specific infections and other skin conditions need to be properly diagnosed and treated appropriately.

Until the rash goes away, it can be soothed by:

• Calamine lotion.

• Antihistamine tablets (but see above).

• Avoiding very hot water.

• Avoiding getting too hot, either in bed or out of it.

• Trying to use hypoallergenic skin products and soap - these are designed to irritate your skin less.

See also Dermatitis.