Fifth Disease (Erythema Infectiosum)

Fifth disease was so named because it was the fifth pink-red infectious rash to be described by doctors.

With Fifth disease:

• Your child has a bright red or rosy rash on both cheeks for 1 to 3 days ("slapped cheek" appearance). 
• The rash on the cheeks is followed by a pink lacelike or netlike rash on the arms and legs (mainly on the thighs and upper arms). 
• The "lacy" rash comes and goes several times for 1 to 3 weeks. 
• our child has a low-grade fever (less than 101°F, or 38.4°C) or no fever at all. 

Fifth disease is caused by a virus called human parvovirus B19.

This is a very mild disease with either no symptoms or a slight runny nose and sore throat. The lacelike rash may come and go for 5 weeks, especially after warm baths, exercise, and sun exposure.

No treatment is necessary. This distinctive rash is harmless and causes no symptoms that need treatment.

Yes. If a pregnant woman is exposed to a child with Fifth disease, she should see her obstetrician. An antibody test will be done to see if the mother already had the disease and is therefore protected. If she does not have antibodies against the disease, the pregnancy will need to be monitored closely. Some babies develop complications if they were infected with Fifth disease before birth. 10% develop severe anemia and 2% may die. Birth defects, however, are never a result of this virus.

Children will come down with the rash 10 to 14 days after they have been exposed to the virus. The disease is contagious during the week before the rash begins. Therefore, exposed children should try to avoid contact with pregnant women, but that can be difficult. Once a child has the bright red or lacy rash, he is no longer considered contagious and does not need to stay home from day care or school.

Most adults who get Fifth disease develop just a mild pinkness of the cheeks or no rash at all. Adults develop joint pains, especially in the knees, more often than a rash. These pains may last 1 to 3 months. Taking ibuprofen usually relieves these symptoms. An arthritis workup is not necessary for joint pains that occur after exposure to Fifth disease.

If you feel that your child needs immediate medical care.

• Your child develops a fever over 104° F (40° C). 
• You have other concerns or questions.

Written by B.D. Schmitt, MD, author of "Your Child's Health," Bantam Books.
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.