Smallpox: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Smallpox?
An infectious disease doctor, a doctor who treats illnesses caused by germs, would lead care for smallpox. An emergency medicine doctor, a doctor who treats sudden and serious illness, may also be involved. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is smallpox?
Smallpox was an infectious disease caused by the variola virus. It was contagious, which means it spread from one person to another. Smallpox has been eradicated, which means it has been wiped out. No cases of natural smallpox have happened since 1977. The World Health Assembly declared smallpox eradicated in 1980.
Smallpox no longer occurs naturally, but it is possible that the virus could be used in a biological attack. This is unlikely, but public health authorities prepare for it.
Symptoms
People who had smallpox had a fever and a distinctive skin rash that got worse over time. The illness began with a sudden fever of 101 degrees Fahrenheit or higher, followed by a rash of firm, deep blisters.
Doctors look for these signs:
- A fever 1 to 4 days before the rash, along with at least one of these: feeling very weak, headache, backache, chills, vomiting, or severe belly pain.
- Blisters that are firm, hard, and round.
- Blisters that are all in the same stage on any one part of the body.
- Most sores on the face and on the arms and legs far from the body.
Most people with smallpox recovered, but about 3 out of every 10 people with the disease died. Many survivors have permanent scars over large areas of their body, especially their faces. Some are left blind.
Causes and who gets it
The variola virus causes smallpox. Before it was eradicated, it was mainly spread by direct and fairly prolonged face-to-face contact between people. It could also spread through coughing and sneezing.
Because smallpox is gone, people no longer catch it naturally. The main concern today is a possible attack. Smallpox vaccines are not recommended for the general public because smallpox has been eradicated. If there were an outbreak, health officials would use smallpox vaccines to control it.
How doctors diagnose it
Doctors ask about symptoms before the rash, contact with sick people, especially anyone with a rash, and recent travel.
Many illnesses cause a rash with blisters. It is unlikely, though possible, that a person with such a rash has smallpox. If the risk stays high after expert advice, the case is treated as a probable smallpox case and a medical and public health emergency.
Lab testing for the virus is done in a CDC Laboratory Response Network lab. The test is called PCR. A positive result means it found the DNA of the variola virus in a sample. Monkeypox, also called mpox, can look like smallpox. Mpox causes swelling in the lymph nodes, in places such as the neck and armpit, while smallpox does not.
Treatment
Treatment of smallpox generally involves supportive care, which means care that helps with symptoms. A person treated in a health care setting needs isolation and infection controls. There is no treatment that has been tested in people who are sick with smallpox and proven effective.
Two drugs are approved by the FDA for smallpox. In July 2018, the FDA approved tecovirimat (Tpoxx), the first drug with an indication for treatment of smallpox. In June 2021, the FDA approved brincidofovir (Tembexa). There are limited efficacy data in humans for tecovirimat.
A smallpox vaccine can prevent or lessen the illness if given within 2 to 3 days of the first exposure. It may decrease symptoms if given within the first week of exposure.
When to see a doctor
Smallpox no longer occurs naturally, so most rash illnesses are something else. Even so, a fever of 101 degrees Fahrenheit or higher followed by a rash of firm, deep blisters is how doctors define a smallpox case, so it should be evaluated by a doctor. If doctors think the risk of smallpox is high, they treat the case as a medical and public health emergency. Call 911 or go to the emergency room if you have trouble breathing, chest pain, fainting, a sudden change in mental state such as confusion, or bleeding that will not stop.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care or concierge doctor can see you for a fever or rash and help you reach hospital and public health care if needed.
Common questions
Does smallpox still exist?
No. Smallpox has been eradicated, and no cases of natural smallpox have happened since 1977. The World Health Assembly declared it eradicated in 1980.
How deadly was smallpox?
About 3 out of every 10 people with smallpox died. Many survivors have permanent scars, especially on their faces, and some are left blind.
Is there a treatment for smallpox?
Treatment is mostly supportive care. The FDA has approved two drugs for smallpox, tecovirimat and brincidofovir. Neither has been tested in people who are sick with smallpox and proven effective.
Can the smallpox vaccine help after someone is exposed?
Yes. A smallpox vaccine can prevent or lessen the illness if given within 2 to 3 days of the first exposure. It may decrease symptoms if given within the first week of exposure.
Is smallpox the same as mpox?
No. They are different diseases that can look alike.
Sources
- Centers for Disease Control and Prevention - About Smallpox
- Centers for Disease Control and Prevention - Diagnosis and Evaluation of Smallpox
- Centers for Disease Control and Prevention - Clinical Treatment of Smallpox
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
