Clinical

There are several kinds of skin infections caused by viruses, and these are best considered in the four categories that group together similar symptoms for the purpose of differential diagnosis:

• maculopapular rashes

• vesicular rashes

• wart-like lesions

• haemorrhagic rashes.

Maculopapular rashes

These skin rashes can be caused by a variety of different viruses. Clinically it is difficult to distinguish between the viral causes of these maculopapular rashes. Studies have shown that only a small percentage of these rashes are clinically diagnosed accurately.Figure 41.1 shows a typical maculopapular rash. Table 41.1 provides information on the laboratory diagnosis of virus infections associated with maculopapular skin rashes.

Rubella

Rubella is caused by rubella virus. It produces a mild illness with a maculopapular skin rash. It causes severe congenital damage in children born to mothers who acquire infection in the first 12 weeks of pregnancy. Because of this, women should receive rubella virus vaccine before becoming pregnant. They should also seek advice from a healthcare professional if they are in contact with a rubella-like illness in the first 20 weeks of pregnancy. Patients are infectious for one week either side of the onset of rash.