Three cases of fatal anaphylaxis to antibiotics in patients with prior histories of allergy to the drug.

Three cases of fatal anaphylaxis to penicillin and cephalexin are described. All three patients had prior histories of severe allergic reactions to the antibiotics they were given. The radioallergosorbent test was positive on post-mortem blood to the appropriate antibiotic in all three cases. RAST can be performed on post-mortem specimens of serum, sodium fluoride-treated blood, or whole blood.