Eczema vaccinatum

A rare and severe complication of smallpox vaccination

An infant with eczema vaccinatum

Eczema vaccinatum is a rare and severe complication that can occur in individuals with a history of atopic dermatitis or other forms of eczema following exposure to the smallpox vaccine. This condition is characterized by a widespread vesicular and pustular rash, fever, and systemic illness. It is considered a medical emergency due to its potential severity and complications.

Pathophysiology

Eczema vaccinatum occurs when the live vaccinia virus used in the smallpox vaccine spreads in the skin of individuals with compromised skin barriers, such as those with eczema. The virus can replicate extensively in the skin, leading to widespread lesions and systemic symptoms. The condition is more likely to occur in individuals with active or a history of atopic dermatitis.

Clinical Presentation

Patients with eczema vaccinatum typically present with a sudden onset of fever, malaise, and a rapidly spreading vesicular rash. The rash often begins at the site of vaccination and spreads to other areas of the body, including areas affected by eczema. The lesions can become pustular and may coalesce into larger areas of skin involvement.

Diagnosis

The diagnosis of eczema vaccinatum is primarily clinical, based on the history of recent smallpox vaccination and the characteristic rash in a patient with a history of eczema. Laboratory confirmation can be obtained by isolating the vaccinia virus from skin lesions.

Management

Management of eczema vaccinatum involves supportive care and antiviral therapy. The use of vaccinia immune globulin (VIG) is recommended for severe cases. Antiviral medications such as cidofovir may also be used. Hospitalization is often required for severe cases to manage complications and provide supportive care.

Prevention

Preventing eczema vaccinatum involves screening individuals for a history of eczema or atopic dermatitis before administering the smallpox vaccine. Individuals with active eczema or a history of the condition should not receive the smallpox vaccine due to the risk of developing eczema vaccinatum.

Prognosis

With prompt recognition and appropriate treatment, the prognosis for eczema vaccinatum can be favorable. However, severe cases can lead to significant morbidity and, in rare instances, mortality.

Related pages

• Smallpox vaccine
• Atopic dermatitis
• Vaccinia virus