| Mechanism | Examples | Type of reaction generated |
| Complete allergens | ||
| Foreign macromolecules | Recombinant proteins (eg, cetuximab, rituximab) | Type I |
| Insulin and other hormones | ||
| Enzymes and protamine | ||
| Antisera | ||
| Vaccines | ||
| Functionally-multivalent chemicals | Quaternary ammonium compounds (eg, neuromuscular-blocking agents, such as succinylcholine) | |
| Carboxymethyl cellulose | ||
| Direct haptenation | ||
| Beta-lactam antibiotics | Type I Type II Type III Type IV | |
| Penicillamine | ||
| Heavy metals (gold, cisplatinum) | ||
| Metabolism to haptenic form* | ||
| Sulfonamides¶ | Type I Type II Type III Type IV | |
| AcetaminophenΔ | ||
| Phenacetin¶ | ||
| Procainamide¶ | ||
| Halothane◊ | ||
| Direct stimulation of immune receptors (the p-i concept) | ||
| Sulfamethoxazole | Type IV | |
| Abacavir | ||
| Lidocaine, mepivacaine | ||
| Carbamazepine, lamotrigine | ||
| Flucloxacillin§ | ||
| Allopurinol/oxypurinol | ||
