Eczema Vaccinatum is a rare and severe antagonistic reaction to a vaccination of smallpox. It is described as developing serious local or scattered, umbilicated, vesicular, crusting skin rash in the neck, face, chest, abdomen, upper hands and limbs, caused by a pervasive skin infection in those individuals with previous established problems with the skin for example atopic dermatitis or eczema, even though these conditions aren’t active at the time of the vaccination.

Other symptoms and signs include fever and facial edema. The situation can be fatal if severe and if left not treated. Survivors are very likely to have some scarring or pockmarks.

Smallpox vaccine shouldn’t be administrated to those individuals with any past of eczema. Due to the danger of transmission, it also shouldn’t be administrated to individuals in contact with others having a current active case of eczema and who haven’t been vaccinated. Individuals with additional skin problems – for instance atopic dermatitis, herpes zoster impetigo, or burns – also have a threat of developing “eczema vaccinatum” and shouldn’t be vaccinated for smallpox.

Eczema is likewise linked with an increased risk of complications to other vesiculating viruses such as chickenpox; this is known as eczema herpeticum.