By Drs. Sally Robinson and Keith Bly

Fifth disease is a common viral infection that normally appears in school-age children in late winter and early spring. It is caused by parvovirus B19, which is a human virus and not the same parvovirus that affects pets. Humans cannot pass parvovirus B19 to pets, and pets cannot pass the virus to humans. It is named “fifth disease” because it was the fifth rash-related infection identified.

Fifth disease begins with a low-grade fever, headache and mild cold-like symptoms. These symptoms disappear in a few days and then a distinctive red rash appears on the face that makes a child appear as though she has been slapped across the cheek. The rash spreads to the arms, legs and trunk. Other symptoms include swollen glands, red eyes, sore throat, diarrhea, unusual rashes that look like blisters or bruises and, in teenagers and adults, joint swelling and pain. The rash may take one to three weeks to clear completely, and exposure to sunlight, heat, exercise and stress may reactivate it until it fades completely.A person with parvovirus B19 is contagious before the rash appears, when he has cold-like symptoms. It is spread through fluids from the mouth, nose or throat, especially droplets from coughs or sneezes, of someone infected with the virus. The time between initial contact with the virus and when symptoms appear is four to 28 days, and all symptoms disappear within one to two weeks. In a few cases, older children and adults may have joint swelling and pain that last for a few months up to a few years.There is no vaccine to prevent fifth disease and no way to prevent the spread of the virus, but frequent handwashing is a good way to prevent the spread of any infection.Because it is a virus, fifth disease cannot be treated with antibiotics. The illness is usually mild and doesn’t require medication. After the mild cold symptoms pass, the only treatment required may be a topical anti-itch cream, to relieve the discomfort that the rash can cause.In most cases, there are no complications associated with the virus, and by the time the rash appears, children feel well and are back to their normal activities. However, children with weakened immune systems or certain blood disorders (such as certain types of anemia) may become very ill because parvovirus B19 can temporarily slow down or stop the production of red blood cells. If you are pregnant and develop a rash or have been exposed to someone with fifth disease, call your obstetrician, as fifth disease can be dangerous to a developing fetus.

Call your child’s doctor if she develops a rash, especially if the rash covers the majority of her body and is accompanied by other symptoms.

Dr. Sally Robinson is a pediatrician in the division of children’s special services at the University of Texas Medical Branch at Galveston. She teaches medical students about caring for children with chronic medical conditions. Dr. Keith Bly is a hospitalist and assistant professor of pediatrics at UTMB.

The Your Health column is written by health and medical experts at the University of Texas Medical Branch at Galveston. The column focuses on topical health issues that we believe are of interest to your readers. It is e-mailed every Tuesday. If you have any questions about the column, or would like to suggest topics, please contact John Koloen, media relations specialist, at (409) 772-8790 or email jskoloen@utmb.edu.