What is the recommended treatment with prednisone (corticosteroid) for a delayed allergic reaction?

Prednisone Treatment for Delayed Allergic Reactions

For severe delayed allergic reactions, prednisone should be administered at 0.5-1 mg/kg/day for 3-10 days until symptoms resolve to grade 1 or less, with treatment beginning 1 day before any known allergen exposure and continuing for 5 days after exposure for preventive purposes. 1

Types of Delayed Allergic Reactions

Delayed allergic reactions differ from immediate hypersensitivity reactions in their mechanism and presentation:

• T-cell mediated reactions typically occur 24-72 hours after exposure
• Can manifest as various clinical phenotypes:
  • Maculopapular exanthems
  • DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms)
  • Stevens-Johnson syndrome
  • Toxic epidermal necrolysis
  • Contact dermatitis

Prednisone Dosing Protocol

For Treatment of Active Delayed Reactions:

• Initial dose: 0.5-1 mg/kg/day 1
• Duration: Continue until symptoms resolve to grade 1 or less (typically 3-10 days) 1
• Administration timing: Take in the morning before 9 am to minimize adrenal suppression 2
• Tapering: Gradually decrease the dose in small increments rather than abrupt discontinuation 2

For Prevention of Recurrent Reactions:

• Begin: 1 day before anticipated allergen exposure 3
• Continue: For 5 days total (including the day before and days after exposure) 3
• Dosing: Same as treatment dosing (0.5-1 mg/kg/day) 1

Special Considerations

Radiographic Contrast Media (RCM) Reactions:

For patients with history of severe delayed reactions to contrast media:

• Begin glucocorticoid premedication 1 day before procedure
• Continue for 5 days total
• Consider using a non-cross-reactive contrast agent from a different group 3

Medication Administration Tips:

• Take with food or milk to reduce gastric irritation 2
• Consider antacids between meals to prevent peptic ulcers with large doses 2
• For multiple daily doses, space evenly throughout the day 2

Monitoring and Follow-up

• Assess response within 24-48 hours of initiating therapy
• Monitor for adequate symptom control
• Watch for potential adverse effects of corticosteroids
• Avoid prolonged use due to potential side effects 1

Cautions and Contraindications

1. Allergy to prednisone: Although rare, allergic reactions to corticosteroids can occur 4, 5

   • Symptoms may include urticaria, exanthematous eruptions, or anaphylaxis
   • If suspected, consider alternative corticosteroids (dexamethasone or methylprednisolone may be tolerated) 5

2. Avoid long-term use: Reserve corticosteroids for acute exacerbations in short courses 1

3. Tapering: Never stop abruptly after prolonged use 2

Alternative Approaches

For patients with contraindications to prednisone or steroid allergy:

• Antihistamines (H1 blockers) may be sufficient for mild delayed reactions
• For severe cases with steroid allergy, consider alternative immunosuppressants like cyclosporine 3
• Skin testing with delayed readings at 48 and 72 hours may help identify non-cross-reactive alternatives 3

Efficacy Evidence

In chronic urticaria studies, a short course of prednisone (starting with 25 mg/day for 3 days) induced remission in nearly 50% of antihistamine-resistant patients, with effects often noticeable within 24 hours of the first dose 6.

Remember that while corticosteroids are effective for treating delayed allergic reactions, they should be used judiciously and for the shortest duration necessary to control symptoms.