Appendix 4: Drug Allergy

I

Immediate (IgE mediated)

Allergen binds to IgE on basophils or mast cells, resulting in release of inflammatory mediators

Within 1 hour (may be within 1–6 hours)

Penicillin anaphylaxis, angioedema

Blood products

Polypeptide hormones

Vaccines

Dextran

II

Delayed; cytotoxic

Cell destruction occurs because of cell-associated antigen that initiates cytolysis by antigen-specific antibody (IgG) and complement. Most often involves blood elements

Typically >72 hours to weeks

Penicillin, quinidine, quinine, heparin, thiouracils, sulfonamides, methyldopa

III

Delayed; immune complex

Antigen–antibody (IgG or IgM) complexes form and deposit on blood vessel walls and activate complement. Result is a serum sickness-like syndrome or vasculitis

>72 hours to weeks

Penicillins, sulfonamides, minocycline, hydantoins

IV

Delayed; T cell–mediated

Antigens cause activation of T lymphocytes, which release cytokines and recruit effector cells

>72 hours

IVa

Th1 cells, interferon-γ, monocytes, and eosinophils respond to the antigen

1–21 days

Tuberculin reaction, contact dermatitis

IVb

Th2 cells, interleukin-4, and interleukin-5 respond to the antigen

1–6 weeks

Maculopapular rashes with eosinophilia

IVc

Cytotoxic T cells, perforin, granzyme B, FasL respond to the antigen

4–28 days

Bullous exanthems; fixed drug eruptions

IVd

T cells and interleukin-8 respond to the antigen

>72 hours

Acute generalized exanthematous pustulosis

Amoxicillin

51.4

Trimethoprim–sulfamethoxazole

33.8

Ampicillin

33.2

Iopodate

27.8

Blood

21.6

Cephalosporins

21.1

Erythromycin

20.4

Penicillin G

18.5

Cyanocobalamin

17.9

1. Remove the inciting allergen, if possible.

2. Assess airway, breathing, circulation, and orientation. Support the airway.

3. Cardiopulmonary resuscitation: Start chest compressions (100/min) if cardiovascular arrest occurs at any time.

4. Administer epinephrine 1:1000 (adults: 0.3–0.5 mg; children: 0.01 mg/kg) IM in the lateral aspect of the thigh.

5. Place the patient in a recumbent position.

6. Administer oxygen 8–10 L/min through facemask or up to 100% oxygen as needed; monitor by pulse oximetry, if available.

7. Repeat IM epinephrine every 5–15 minutes for up to 3 injections if the patient is not responding.

8. Establish IV line for venous access. Keep line open with 0.9% saline solution. For hypotension or failure to respond to epinephrine, administer 1–2 L at a rate of 5–10 mL/kg in the first 5–10 minutes. Children should receive up to 30 mL/kg in the first hour.

9. Consider nebulized albuterol 2.5–5 mg in 3 mL of saline for lower airway obstruction; repeat as necessary.

10. In cases of refractory bronchospasm or hypotension not responding to epinephrine because a β-adrenergic blocker is ...