Measles

A potentially dangerous viral illness that causes fever and a characteristic rash. Measles mainly affects children, but can occur at any age. The virus is spread primarily by airborne droplets of nasal secretions. It can be transmitted during the incubation period (8–14 days after infection) and up to 7 days after symptoms appear. The illness starts with a fever, runny nose, sore eyes, cough, and a general feeling of being unwell. After 3–4 days, a red rash appears, usually starting on the head and neck and spreading to cover the body. The spots sometimes join to produce large red blotches, and the lymph nodes may be enlarged. After 3 days, the rash starts to fade and the symptoms subside. The most common complications are ear and chest infections, which usually occur 2–3 days after the rash appears. Diarrhoea, vomiting, and abdominal pain also occur. Febrile convulsions (see convulsion, febrile) are also common, but these are not usually serious. Encephalitis occurs in about 1 in 1000 cases, causing headache, drowsiness, and vomiting. Seizures and coma may follow, sometimes leading to brain damage or even death. In very rare cases, a progressive brain disorder known as subacute sclerosing panencephalitis develops years later. If measles occurs during pregnancy, the fetus dies in about a fifth of cases. However, there is no evidence that measles causes birth defects. There is no specific treatment for measles. Plenty of fluids and paracetamol are given for fever, and antibiotic drugs may be given to treat bacterial infections that occur as complications. To help prevent measles, immunization with the MMR vaccination is recommended at 12–15 months of age. This produces immunity in about 90 per cent of cases, with a booster shot given before school or nursery school entry.