Serum sickness in humans is a reaction to proteins in antiserum derived from a non-human animal source, occurring 5–10 days after exposure.
The term serum sickness–like reaction (SSLR) is occasionally used to refer to similar illnesses that arise from the introduction of certain non-protein substances, such as penicillin.
It usually resolves naturally, but may be treated with corticosteroids, antihistamines, analgesics, and (in severe cases) prednisone.
[3] Serum sickness is a type III hypersensitivity reaction, caused by immune complexes.
[2] When an antiserum is given, the human immune system can mistake the proteins present for harmful antigens.
The body produces antibodies, which combine with these proteins to form immune complexes.
[2][3] These sera or antitoxins are generally given to prevent or treat an infection or envenomation (venomous bite).
However, according to the Johns Hopkins Bloomberg School of Public Health, routinely recommended vaccinations to the general population in the U.S have not been shown to cause serum sickness, as of 2012.
This is important if a patient has received an antitoxin before, as the serum sickness caused can be worse and occur more quickly.