What is the management for an injection site reaction?

Management of Injection Site Reactions

Injection site reactions should be managed based on severity, with mild to moderate reactions treated with cold compresses, antihistamines, and topical corticosteroids, while severe reactions require immediate medical attention including epinephrine administration for anaphylaxis. 1

Classification and Initial Assessment

Injection site reactions (ISRs) present as a constellation of symptoms including:

• Swelling
• Erythema
• Pruritus
• Pain around the injection site
• Possible formation of subcutaneous nodules 2, 3

ISRs occur with an incidence rate of 0.5-40% with biological agents 3 and can be classified as:

1. Immediate reactions - occurring within minutes to hours
2. Delayed reactions - occurring 1-14 days after administration 1

Management Algorithm Based on Severity

Mild to Moderate Reactions (Grade 1-2)

• Apply cold compresses to the affected area
• Administer H1/H2 antihistamines:
  • Diphenhydramine 50 mg orally/IV
  • Ranitidine 50 mg orally/IV 4, 1
• Apply topical corticosteroids to reduce inflammation
• If reaction occurs during infusion: slow rate or temporarily stop infusion 4
• For ongoing infusions: restart at 50% rate and titrate to tolerance 4

Severe Reactions (Grade 3-4)

1. Stop medication administration immediately

2. Maintain IV access

3. Assess ABCs (Airway, Breathing, Circulation)

4. If anaphylaxis is suspected:

   • Administer epinephrine 0.2-0.5 mg (1 mg/mL) IM into lateral thigh
   • Repeat every 5-15 minutes if needed
   • Administer normal saline 1-2 L IV at 5-10 mL/kg in first 5 minutes
   • Give H1/H2 antagonists: diphenhydramine 50 mg IV plus ranitidine 50 mg IV
   • For bradycardia: atropine 600 μg IV
   • For hypotension: dopamine or vasopressin
   • If patient is on beta-blockers: glucagon 1-5 mg IV over 5 minutes
   • Administer corticosteroids: 1-2 mg/kg IV methylprednisolone every 6 hours 4, 1

5. Monitor vital signs until resolution

6. Observe for 24 hours if severe reaction occurred 4

Special Considerations

Prevention Strategies

• Proper injection technique:
  • Rotate injection sites
  • Inject into appropriate tissue
  • Cleanse skin before injection 1
• Consider premedication for patients with history of reactions:
  • Corticosteroids plus antihistamines before administration 4
• Patient education on proper self-injection techniques 1

Documentation Requirements

• Pre-injection assessments
• Description and grading of the reaction
• Management approach used
• Patient response to interventions 1

Rechallenge Considerations

• Rechallenge after severe reactions (grade 3 or higher) is discouraged 4, 1
• For patients who experienced mild to moderate reactions, consider:
  • Using a different formulation or concentration if available 5
  • Premedication before subsequent doses 4

Important Caveats

• Most ISRs are not true allergic or immunogenic reactions and don't necessitate discontinuation of treatment 3
• ISRs are not correlated with drug efficacy or development of antidrug antibodies 3
• Delayed reactions may occur up to 8 days following a second injection, as seen with certain monoclonal antibodies 6
• For persistent or severe delayed reactions, a course of systemic corticosteroids may be required 6
• Patients with a history of penicillin hypersensitivity may also experience allergic reactions when treated with cephalosporins 7

Remember that prompt recognition and immediate medical attention are essential for managing severe injection site reactions, particularly those progressing to anaphylaxis 4, 1.