Fixed drug reactions

As the name suggests, fixed drug reactions are oval-shaped lesions that are either solitary or multiple, and sometimes have a blistered centre. They occur quickly after taking the sensitising drug (within a few hours) and will reoccur, usually in the same place, each time the drug is taken see Box 13.3. They leave behind a hyperpigmented area of skin. The lesions can occur anywhere on the body but frequently appear on mucosal surfaces including lips and genitalia.

Box 13.3 Common drugs that can cause fixed drug reactions   Phenolphthalein Paracetamol   Tetracyclines Chlordiazepoxide   Sulphonamides Non-steroidal   Quinine anti-inflammatories