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Evaluate a Rash Illness Suspicious for Smallpox

Caution: Use this tool only when there is no release or circulation of smallpox.

  1. Answer all questions. If a question does not apply to your patient, or if you cannot answer the question, click "No", or "Unknown".
  2. After you complete the questions, press the "Evaluate Risk" button.

Type of Rash Illness

1. Does the patient have an acute, generalized rash on the body, with vesicles or pustules?

If yes, institute airborne and contact precautions.
If no, and there is no known release or circulation of smallpox, there is no basis for calculating risk for smallpox.

Major Smallpox Criteria more information

2. Does the patient have classic smallpox lesions (i.e., deep-seated, firm/hard, round well-circumscribed vesicles or pustules)?

3. Are the vesicles or pustules in the same stage of development? For example, on any part of the body (e.g., face or arm) are lesions all vesicles or pustules?

4. Did the patient develop a fever of 101°F or greater 1-4 days before rash onset?

5. Did the patient have any of the following symptoms 1-4 days before rash onset?

Minor Smallpox Criteria more information

6. Does the patient have symptoms meeting minor criteria? Check all that apply.


Page last reviewed February 6, 2007
Page last modified May 21, 2004

  • Content source: CDC Emergency Risk Communication Branch (ERCB), Division of Emergency Operations (DEO), National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)

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