Eczema vaccinatum is an unusual complication of smallpox vaccination seen in people with underlying skin conditions like eczema and impetigo. In these patients, exposure to the vaccine results in a spreading rash of vesicles and skin irritation. There is a risk of developing severe complications, and patients with this condition may need to be hospitalized for treatment. This condition is not smallpox, but rather an adverse reaction to the smallpox vaccine.
There are two ways people can develop eczema vaccinatum. The first is through direct inoculation with the smallpox vaccine, and the other is through contact with someone who has been recently inoculated, who can shed minute amounts of vaccinia as they heal from the vaccine. In both cases, a rash starts, accompanied with fluid-filled bumps, and can spread quickly across the whole body. If the patient was previously unaware of the underlying skin condition, the reaction can come as an unexpected and very unpleasant surprise.
Treatment of eczema vaccinatum can include administration of vaccinia immune globulin to halt the reaction, along with supportive therapy in intensive care to address concerns like high fever, ocular damage, and difficulty breathing. Fluids may be required and some patients need mechanical ventilation to address breathing problems. With hospital care, a patient may recover, although some small, scarred lesions may be left behind as a legacy of the rash, especially if the patient picked or scratched during the episode.
With the global eradication of smallpox, a significant public health victory, the need for smallpox vaccinations is very low. Vaccines may be recommended for some members of the armed forces, as well as researchers who come into contact with the world’s remaining stores of smallpox. In individuals with a history of skin problems, vaccination is contraindicated, and people who need to be vaccinated should avoid contact with unvaccinated family members with skin conditions while they heal from the vaccination. Eczema vaccinatum can be as especially serious concern with infants. Before receiving a smallpox vaccine, people should go over their medical history and ask about any special risks to family members.
Doctors rarely see this condition, thanks to the limited number of smallpox vaccinations being administered. People who need smallpox vaccines or who live with people who have been vaccinated should watch out for potential complications of the vaccination and seek medical treatment promptly if conditions like eczema vaccinatum develop. Early treatment can greatly improve the prognosis, as well as limit permanent skin damage.