A viral exanthem is a rash that occurs in the setting of a viral illness. There are many viral illnesses that can result in a rash. Some of the more notable and common viruses include hand-foot-mouth disease (enterovirus), measles (paramyxovirus), chickenpox (varicella-zoster virus) and roseola (herpesvirus 6). A viral infection of any kind in children can cause a rash even if the exact virus is not known.
The rash of a viral exanthem typically appears as numerous red spots that can be spread out over the entire body or just in one area. The red spots can all group together and can be itchy during the flare of the rash. While concerning, this rash typically appears at the end of an illness after the fever has reduced.
The body’s immune response to a virus or the virus replicating within skin cells is believed to result in the appearance of a rash.
Few viral illnesses are treated with oral medications in healthy patients. Most often the virus has to run its course and your body will mount an immune response to clear the active infection. Occasionally an antiviral medication (for example: acyclovir) can be used to help fight the infection.
Topical steroids can be used to help alleviate inflammation in the skin associated with the rash or exanthem. Sometimes an intramuscular injection of steroid or a short course of oral steroids can be used if the inflammation is severe. Vaccinations can help prevent the occurrence of some viral exanthems such as chickenpox, shingles, measles, mumps, and others.