Jan. 22, 2003
A case of smallpox passes through several stages, from the earliest phase, which is not contagious, through the disappearance of all scars several weeks later.
The following stages have been identified by the U.S. Centers for Disease Control and Prevention and the World Health Organization:
Incubation (average, 12 to 14 days)
A person who has been exposed to smallpox feels fine during this time and is not able to spread the disease to others.
Initial Symptoms (2 to 4 days)
Early symptoms may seem like flu. Smallpox may be contagious during this time, but much less contagious than in the next phase. The symptoms include:
- Fever
- Head and body aches
- High fever (101 to 104 degrees)
- Too sick for normal activities
Early Rash (about 4 days)
This is the beginning of the most contagious stage. A rash appears and spreads quickly. The rash also evolves in stages, and all bumps in a particular area of the body go through these stages at the same time, making smallpox distinctly different from chicken pox.
- First day – A rash emerges, initially as red spots in the mouth that turn into sores, break open and spread the virus into the mouth and throat. About the same time the sores break, a skin rash appears, beginning on the face and spreading to the arms, legs, hands and feet.
- First and second day – Within 24 hours, the rash usually spreads all over the body, but is still concentrated on the face, arms and legs. The fever usually falls and the person may feel better.
- Third day – The red spots turn into raised bumps.
- Fourth day – The bumps fill with a thick fluid and often have a depression in the center that looks like a bellybutton or nipple. This type of bump is typical of smallpox. Fever may rise again.
Pustular Rash (about 5 days)
The sores turn into pustules — raised, firm bumps that feel as if there's a round object such as a BB under the skin. The disease is still contagious.
Scabbing (about 5 days)
The pustules develop scabs. Most sores scab over by the end of the second week after the rash appears. The disease is still contagious, but much less so than before.
Scabs Fall Off (about 6 days)
As the scabs drop off, they leave marks that turn into pitted scars. The person remains contagious until all scabs are gone.
Complications
Many smallpox patients die of complications, which can include encephalitis, pneumonia and additional skin infections. Blindness can result from eye infections.
— Lisa Ellis
