Last Updated

22 Nov 2002

Source: Wall Street Journal, November 22, 2002.

A Rash of False Alarms Helps Smallpox Diagnosis

By MARILYN CHASE, Staff Reporter of THE WALL STREET JOURNAL

Tormented by a rash and disoriented by fever, a retired seamstress dialed 911 from her mobile home in North Fort Myers, Fla., on the afternoon of Oct. 22.

Paramedics rushed 59-year-old Ann Hawkins to Cape Coral Hospital in critical condition. When doctors saw the red lesions on her face and arms, they put her in isolation and closed the emergency room. The hospital alerted state and county health officials, who sent word to the U.S. Centers for Disease Control and Prevention in Atlanta that Florida had a case that looked suspiciously like smallpox .

In a world shaken by fears of bioterrorism, vigilance about the lethal viral scourge is higher today than it has been in the three decades since the U.S. stopped vaccinating its citizens. Natural smallpox has been eradicated since 1980.

But amid post-9/11 jitters, federal health officials have received more than two dozen possible smallpox reports during calendar 2002.

Fortunately, all the reports so far, including the case of Ann Hawkins, were false alarms. Two-thirds of such reports turn out to be chickenpox, and other impostors include herpes, impetigo, insect bites, and infections like hand, foot and mouth disease. Ms. Hawkins, diagnosed with a probable drug reaction, now is recovering at home. "I'm doing better," she says, adding, "I'm not contagious."

The CDC is using such false alarms to help educate American physicians about how to diagnose smallpox, a disease most of them have never seen. Unlike the story of "the boy who cried wolf," these mistaken reports haven't inured officials to danger. On the contrary, smallpox false alarms are being analyzed to sharpen diagnostic skills and heighten public health awareness, says Inger Damon, chief of CDC's poxvirus section.

Dr. Damon offers four case histories that show how many conditions can masquerade as smallpox, and how to distinguish them from the real thing.

Case 1: A 10 year-old Central American boy with pustules on his face had been seen by missionaries and reported to CDC. The clue: while smallpox rash is preceded by fever, the boy's fever and rash appeared together. The diagnosis: chickenpox.

Case 2: A 50-year-old European immigrant developed a rash on her legs. Although she had been vaccinated against smallpox years earlier, her physician worried it was a breakthrough case. The clue: again, the patient had no fever before her rash. The probable diagnosis: contact dermatitis from a recent hiking trip.

Case 3: A 28-year-old man walked into an urgent-care clinic complaining of headache, fever and rash. The clue: His lesions were in different stages and clustered on his trunk, and his fever spiked after the rash. True smallpox lesions are synchronized in same stage and concentrated on the face and extremities. The diagnosis: shingles -- a flare-up of varicella zoster, the chickenpox virus -- along nerve pathways.

Case 4: A 29-year-old laboratory scientist had headache, fever, rash and fluid in her lungs. Working mainly on vaccinia -- the virus used in smallpox vaccine -- the scientist also had recently acquired a large collection of poxvirus samples from a colleague. Officials feared the collection might have contained mislabeled smallpox or monkeypox, a related virus. The clue: despite the rash, she didn't feel as sick as smallpox patients do. Her diagnosis: disseminated vaccinia, due to lab exposure.

Analyzing such false alarms led CDC doctors to develop an algorithm for how to tell smallpox from common rashes.

Major smallpox characteristics include:

1. Fever above 101 degrees one to four days before the rash, combined with headache, backache, chills, stomach distress or profound weakness.

2. Classic smallpox lesions are firm, round and deep-seated in the skin, like an imbedded pea. Later, they may develop a dimple in the center.

3. In one part of the body, smallpox lesions will all be in the same stage of development -- for example, all blisters or all scabs -- but not a mix.

Minor smallpox criteria include:

1. Smallpox spots appear in a centrifugal pattern, clustering more on the face and limbs than on the trunk.

2. First lesions are often inside the mouth or palate, face or forearms.

3. Patient appears very sick, even moribund.

4. Lesions evolve slowly -- first a flat spot, then a raised bump, followed by a fluid-filled blister, a pustule, and finally a scab -- with each stage lasting one to two days.

5. Lesions appear on palms of hands and soles of feet.

The case of Ann Hawkins with its happy ending, was "an excellent learning opportunity for us," says Judith Hartner, director of the Lee County, Fla., health department. "A fire drill, that's what this was."

Steven Wiersma, Florida state epidemiologist, says every hospital and physician should have a copy of the CDC poster, "Evaluating Patients for Smallpox ," now on its Web site, www.cdc.gov. "That's the gold standard," he says.