Question:

I am a teacher at an elementary school. Several of the children in the kindergarten class were diagnosed as having fifth disease. From what I know, it's a viral infection that causes a rash. Can you tell me more?

Answer:

Fifth disease is a viral illness common in children. It is the fifth in a group of once-common rash-associated childhood illnesses that includes measles, rubella and scarlet fever. Children will typically develop a classic "slapped cheek" rash on their face, low-grade fever, malaise, and other typical symptoms of a viral infection. Fortunately, it usually runs its course in a week or so with complete resolution of symptoms. Interestingly, an estimated 20 percent of adults and children who are infected with parvovirus B19 have no symptoms other than a slight facial rash.

Fifth disease is caused by the parvovirus, which has led some people to wonder if they can catch it from a dog or cat not vaccinated against parvovirus. Some strains of parvovirus infect only dogs and cats and some infect only humans. The parvovirus B19 subtype that affects humans does not come from dogs, nor can it infect dogs. Fifth disease shows up only in humans, especially children.

The infection is contagious, but by the time the characteristic facial rash appears, the person is probably no longer contagious. About half of all adults have had fifth disease as children and are therefore immune from getting it again. Currently, there's no vaccine against parvovirus B19. Adults who are not immune may catch it by exposure to a child with acute fifth disease. Adults may also develop additional symptoms: prominent joint pain and swelling, especially of the wrists, hands and knees.

Proof of infection can be confirmed by blood tests for antibodies against the virus. Treatment basically involves extra rest, Tylenol or Advil for pain, and time. For a small percentage of children and adults, the virus can result in a severe anemia, which will eventually resolve.

Mitchell Hecht is a physician specializing in internal medicine. Send questions to: Ask Dr. H, Box 767787, Atlanta, Ga. 30076. Because of the volume of mail, personal replies are not possible.