Drug rashes: an introduction

Approximately 2-3% of drugs result in drug rashes (and other skin changes), which are referred to as adverse cutaneous drug reactions (ACDR). This chapter predominantly signposts to mild-moderate ACDR and severe ACDR.

• Approximately 2-3% of drugs result in ACDR

• The mechanism of ACDR can be allergic or non-allergic

• The majority are related to systemic medications but occasionally other treatments such as eye drops and inhalers can be responsible

• Patients more at risk include older patients and those with certain underlying conditions eg HIV, SLE and Sjogren's

• This website divides ACDR in to three groups:
• Mild-moderate ACDR - the majority
• Severe ACDR - this group is sometimes referred to as SCAR (serious cutaneous adverse reactions). This group includes urticaria - angioedema - anaphylaxis, the Stevens-Johnson syndrome and toxic epidermal necrolysis, the Drug Hypersensitivity syndrome (the DRESS syndrome), and erythroderma
• Drugs associated with photosensitivity

• This chapter excludes contact allergic dermatitis (refer to the chapter Eczema - contact allergic dermatitis)

• For detailed information on individual drugs the Drug Eruption Reference Manual is a very useful resource