Viral rashes aren't contagious but the viruses that cause them usually are. Some of the most contagious viral infections that cause a rash include: measles. chickenpox.

Does a viral rash spread?

The rash often first appears on the chest and then spreads to other areas of the body. The rash pattern changes as the illness progresses. It starts with small fluid filled vesicles that look like blisters, but after a few days, the blisters begin to pop, crust, and scab as they heal.

How long do viral rashes last?

Viral rashes are not allergic reactions. They are the result of an infection. Unlike an allergic reaction, viral rashes usually do not cause itching or pain. Viral rashes usually go away after a few days, but may last up to 2 weeks.