Common Drug Hypersensitivities (Drug Allergy)

Overview

Drug hypersensitivity, also known as drug allergy, happens when a person’s immune system reacts strongly to a medication they have developed sensitivity to, leading to various symptoms and reactions. These reactions can range from mild to severe and can present with different symptoms. Here are some examples of common drug hypersensitivities and their associated symptoms:

Immediate-type drug hypersensitivity:

• Symptoms appear within 16 hours after exposure to the medication
• Common presentations include angioedema (swelling of the deep layers of the skin), urticaria (hives), and anaphylaxis (a severe and potentially life-threatening allergic reaction)
• Common culprits for immediate-type drug hypersensitivity include non-steroidal anti-inflammatory drugs (NSAIDs), neuromuscular blocking agents (NMBA), aspirin, antibiotics, and vaccines.

Non-immediate/delayed allergic drug hypersensitivity:

• These reactions have a delayed onset and can manifest with various cutaneous (skin) symptoms such as:
  • Delayed urticaria (hives appearing hours after exposure)
  • Maculopapular eruptions (small, raised bumps on the skin)
  • Fixed drug eruptions (localized skin reactions)
  • Vasculitis (inflammation of blood vessels)
  • Stevens-Johnson syndrome/toxic epidermal necrolysis (severe skin conditions)
  • Generalized bullous fixed drug eruptions (widespread blistering skin reaction caused by a drug)
  • Drug reaction with eosinophilia and systemic symptoms (DRESS): A severe drug reaction causing rash, high white blood cells (eosinophils) and organ inflammation
  • Acute generalized exanthematous pustulosis (AGEP): Sudden pus-filled bumps on red skin
  • Symmetrical drug-related intertriginous and flexural exanthemas (SDRIFE): Symmetrical rash in skin folds (like armpits or groin)
• Internal organs can also be affected, leading to hepatitis (inflammation of the liver), kidney failure, pneumonitis (inflammation of the lungs), anemia, neutropenia (low white blood cell count), and thrombocytopenia (low platelet count).
• DRESS, Stevens-Johnson syndrome/toxic epidermal necrolysis, and AGEP are severe skin reactions that can lead to serious illness and a high risk of death.

It's important to note that any medication has the potential to cause hypersensitivity reactions. However, these examples highlight some drugs that have been recognized as more likely to do so. If you suspect you may be experiencing a drug allergy or hypersensitivity reaction, it is important to consult with a healthcare professional for proper evaluation and guidance. They can help determine if it is indeed a drug allergy and provide appropriate treatment options.