Fifth disease (also known as erythema infectiosum) is a usually mild disease caused by human parvovirus B19. It got its name because years ago it was listed as the fifth of several common rash-causing illnesses in children. Fifth disease most often affects school-age children, but teenagers and adults who have not been exposed to the virus earlier in life can get infected too.
The early symptoms of fifth disease include a mild fever, headache, and runny or stuffy nose, according to the <a href="http://www.netreturns.biz/healthinfo/BounceLink.aspx?Shortcut=aap" target="_blank">American Academy of Pediatrics</a>. A few days after these symptoms stop, a bright-red rash appears on the face, and then spreads to the torso, arms and legs. 
As the rash spreads, areas affected earlier will fade. The rash usually clears up within a week to 10 days. For a few weeks after the initial rash fades, it may recur in response to heat, exercise or stress. Older children and adults may also have joint aching and swelling, which usually lasts a week or two but can sometimes persist for months. 
Fifth disease spreads through droplets of saliva, sputum or nasal mucus that enter the air when a person coughs or sneezes, or it can be spread when people share eating utensils or drinking cups. 
In most people fifth disease is not serious and no specific treatment is needed. But it can be dangerous for pregnant women, who should contact their healthcare provider if they develop a rash of any kind. The disease can also become serious in people with anemia or with weakened immune systems. These people may need special treatment. 
Reviewed 11/16/2023

What is fifth disease?

Fifth disease is most common in school-age children. It's usually mild, and rarely requires treatment.