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Symptoms
By Mayo Clinic staff
The first symptoms of smallpox usually appear 12 to 14 days after you're infected. During the incubation period of seven to 17 days, you look and feel healthy and can't infect others.
Following the incubation period, a sudden onset of flu-like signs and symptoms occurs. These include:
- Fever
- Overall discomfort
- Headache
- Severe fatigue
- Severe back pain
- Sometimes vomiting, diarrhea or both
A few days later, flat, red spots appear first on your face, hands and forearms, and later on your trunk. Within a day or two, many of these lesions turn into small blisters filled with clear fluid, which then turns into pus. Scabs begin to form eight to nine days later and eventually fall off, leaving deep, pitted scars.
The rash is usually most noticeable on the palms of your hands and the soles of your feet. Lesions also develop in the mucous membranes of your nose and mouth and quickly turn into sores that break open, spreading the virus into your saliva.
- Smallpox disease overview. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/agent/smallpox/overview/disease-facts.asp. Accessed June 6, 2011.
- Smallpox. World Health Organization. http://www.who.int/mediacentre/factsheets/smallpox/en. Accessed June 6, 2011.
- Friedman HM, et al. Smallpox. http://www.uptodate.com/home/index.html. Accessed June 6, 2011.
- Rotz LD, et al. Smallpox as an agent of bioterrorism. In: Mandell JE, et al. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-443-06839-3..X0001-X--TOP&isbn=978-0-443-06839-3&uniqId=230100505-57. Accessed June 6, 2011.
- Damon IK. Smallpox, monkeypox and other poxvirus infections. In: Goldman L, et al. Cecil Medicine. 23rd ed. Philadelphia, Pa.: Saunders Elsevier; 2008. http://www.mdconsult.com/das/book/body/191371208-2/0/1492/0.html#. Accessed June 7, 2011.
- Executive summary: Smallpox response plan and guidelines. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/agent/smallpox/response-plan/files/exec-sections-i-vi.pdf. Accessed June 6, 2011.
- Isaacs SN, et al. Vaccinia virus as the smallpox vaccine. http://www.uptodate.com/home/index.html. Accessed June 7, 2011.
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