Serum sickness is an unusual reaction to any foreign substance in
the body. Venom from insect stings or spider bites and medicines such as
penicillin are common causes of this reaction.
Symptoms of serum sickness usually begin between 7 to 10 days
after the person is exposed to the substance. A person usually feels generally
unwell (malaise) and may have hives, joint pain, fever, headache, and swollen
Having an episode of serum sickness puts a person at high risk for
developing a severe allergic reaction if he or she is exposed to the same
substance in the future. A person should avoid any medicine related to serum
sickness after it has been identified. Venom immunotherapy may be an option to
protect against insect or spider bites that caused the reaction.