- A large number of populations suffer from undesired side effects to pharmaceutical products during the course of their lives.
- These reactions can be classified as expected or A-type reactions and unexpected or B-type reactions.
- The skin is a preferred target organ for B-type reactions. This type of skin reactions occur in 2–3% of hospitalized patients.
- Morbilliform drug rashes are the most often occurring skin reactions to drugs, constituting up to 90% of all reactions, followed by drug-induced urticaria, which constitutes about 6%.
- Severe cutaneous adverse reactions (SCAR) to drugs include:
Anaphylaxis and angioedema.
Photosensitivity.
Drug-induced hypersensitivity syndrome (DIHS)/drug reaction with eosinophilia and systemic symptoms (DRESS)
Bullous drug reactions, including toxic epidermal necrolysis (TEN)