Allergic Drug Reaction

Allergic Drug Reaction – Treatment Overview

Introduction
An allergic drug reaction is an adverse response of the immune system to a medication. It can range from mild skin manifestations, such as rash or urticaria, to severe and life-threatening conditions such as anaphylaxis or Stevens–Johnson syndrome (SJS). Management involves immediate withdrawal of the offending drug, symptomatic relief, and, in severe cases, emergency intervention. Early recognition and prompt treatment are crucial to reduce morbidity and prevent recurrence.

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Treatment Options and Doses

1. Discontinuation of the Offending Drug

• The first and most important step.

• Identify and stop the suspected medication immediately.

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2. Antihistamines (for rash, urticaria, itching)

• Cetirizine: 10 mg orally once daily.

• Loratadine: 10 mg orally once daily.

• Diphenhydramine: 25–50 mg orally or IV every 6–8 hours as needed (sedating).

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3. Corticosteroids

• Topical (for mild localized skin reactions):

  • Hydrocortisone 1% cream/ointment: Apply thinly twice daily.

• Systemic (for moderate to severe reactions):

  • Prednisolone: 0.5–1 mg/kg/day orally for 3–5 days, then taper as symptoms improve.

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4. Epinephrine (for anaphylaxis – life-threatening reactions)

• Epinephrine auto-injector (e.g., EpiPen):

  • Adults: 0.3–0.5 mg intramuscularly (IM) into the mid-thigh.

  • Children: 0.01 mg/kg IM (maximum 0.3 mg per dose).

  • Repeat every 5–15 minutes if symptoms persist.

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5. Supportive Measures

• Oxygen supplementation and IV fluids in severe reactions.

• Hospitalization for monitoring if systemic symptoms occur.

• Airway management in cases of angioedema or respiratory compromise.

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6. Advanced/Severe Reactions (SJS/TEN)

• Admit to hospital (preferably ICU or burn unit).

• Supportive care: fluid and electrolyte management, wound care, infection prevention.

• Intravenous immunoglobulin (IVIG) or immunosuppressants (e.g., cyclosporine) may be considered under specialist care.