Drug AllergyBy :

DESSY ADELIANA

Definition Drug allergy is an immunologically

mediated response to a pharmaceutical and/or formulation (excipient) agent in a sensitized person.

Roland Solensky, David A. Khan. Drug Allergy: An Updated Practice Parameter. Annals Of Allergy, Asthma & Immunology. 2010;105:273

Risk factors Drug-related factors

• Nature of the drug• Degree of exposure (dose, duration, frequency) • Route of administration • Cross-sensitization

Host-related factors• Age • Sex • Genetic factors (HLA type, Acetylator status) • Concurrent medical illness (e.g. Ebstein-Barr Virus (EBV),

human immunodeficiency virus (HIV), asthma) • Previous drug reaction • Multiple drug allergy syndrome

Thong BY, Tan TC. Epidemiology and risk factors for drug allergy. Br J Clin Pharmacol 2011; 71:684-700.

Classification of Adverse Drug Reaction

Drugs Allergies

Benno Schnyder , Werner J.Pichler. Mechanisms of Drug-Induced Allergy. Mayo Clin Pro. 2009;84(3):268-272

Type I drug hypersensitivity

Type II drug hypersensitivity

Diagnosis Based on a detailed history of the onset of

symptoms/signs combined with a temporal relationship between the appearance of those symptoms and drug use/discontinuation.

Marc.A.Riedl, Adrian M.Casillas. Adverse Drug Reactions : Types and treatment options.American Family Physician.2003;68: 1786

Diagnostic test IgE mediated or not Measurement of mediators

- histamine- tryptase- leukotrienes

Measurement of drug-specific IgElevel: •measured by RAST or RIA

Thong BY, Vervloet D.Drug Allergies. FAAAAI.2014

Diagnostic testSkin testuseful in the diagnosis of Ig-E mediated allergy

•skin prick test•intradermal test

Thong BY, Vervloet D.Drug Allergies. FAAAAI.2014

Treatment Acute Immediate Management of IgE-Mediated Reactions Nonserious (mild cutaneous)

reactions: antihistamines 

Serious reactions (anaphylaxis): emergency management A-B-C • IM epinephrine 0.3 mL of a 1:1,000 concentration up to

every 5 minutes in adults or 0.01 mg/kg in children up to a maximum dose of 0.3 mg

• IM promethazine or intravenous diphenhydramine Intravenous fluids (colloids or crystalloids)

Thong BY, Vervloet D.Drug Allergies. FAAAAI.2014

Acute Immediate Management of Non–IgE-Mediated Reactions Nonserious reactions: antihistamines Serious reactions

TEN: High-dose intravenous immunoglobulin (IVIG 1 g/kg/d for 2 days)

Thong BY, Vervloet D.Drug Allergies. FAAAAI.2014

Spesific TreatmentDrug desensitization for IgE-mediated drug allergy

Thong BY, Vervloet D.Drug Allergies. FAAAAI.2014

PREVENTION Patients and family members should

be educated on the generic names of the drugs they are allergic to and other potentially cross-reacting drugs

Thong BY, Vervloet D.Drug Allergies. FAAAAI.2014

 

PROGNOSIS

Drug-induced anaphylaxis is potentially fatal. In SJS/TEN, the reported mortality rate varies

from 30% to 50%. Ocular complications (i.e., nonhealing epithelial defects and visual impairment) SJS/TEN. Persistent dry eyes is the most common.

 

Thong BY, Vervloet D.Drug Allergies. FAAAAI.2014

Summary Drug hypersensitivity results from

interactions between a pharmacologic agent and the human immune system.

Immune-mediated drug hypersensitivity reactions typically pose a predictable, more serious health risk with re-exposure to a drug

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