Serum sickness clinical manifestations

Allergic responses to drugs are mediated by the release of histamine or histamine-like substances, and they commonly present as skin rashes, particularly urticaria. More serious hypersensitivity responses include bronchospasm or the acute, explosive anaphylactic reaction with cyanosis and cardiovascular collapse. A delayed reaction known as serum sickness, although more often associated with such drugs as the penicillins and cephalosporins rather than with serum, manifests clinically 7 to 10 days after receiving the drug or serum as fever, malaise, joint pains, and urticarial skin rashes. 

This form of drug-induced urticaria is most commonly due to penicillin. The manifestations do not arise until at least 3-48 h after the dose of penicillin, and in some circumstances not until 3-4 days afterwards. Transitional forms between this condition and serum sickness are not uncommon clinically, the relationship is attested by the development of joint swellings. 

Anaphylaxis - Clinical manifestations of RMP allergy typically occur as serum sickness and mild cutaneous reactions in 0.5-5% of patients. Severe anaphylactic reaction, though rare, may occur and should be distinguished from flushing due to PZA [51 ]. Prompt diagnosis and treatment by clinicians are vital and can be life saving. 

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