Drug Induced Hypersensitivity Reaction: Causes, Symptoms and Treatment

Running head: DRUG INDUCED HYPERSENSITIVITY REACTION
DRUG INDUCED HYPERSENSITIVITY REACTION
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1DRUG INDUCED HYPERSENSITIVITY REACTION
Discuss how drugs can induce hypersensitivities
Hypersensitive reactions caused by drugs are immune mediated reactions to drugs. The
symptoms can be mild or severe and include rashes, anaphylactic reactions and serum sickness.
Some of the common signs of the drug induced hypersensitivity reactions includes hives, rashes ,
fever, swelling of the skin, shortness of breath, runny nose, wheezing or even severe conditions
such as excessive drop in the blood pressure, seizure and loss of consciousness (Aronson 2015).
Drug related hypersensitive reactions are generally reactions of type B mediated by the acquired
immune reaction. Drug-induced hypersensitivity syndrome (DHS) has many exclusive aspects
that includes a postponed onset, inconsistent degradation of the clinical signs or manifestations
post withdrawal of the responsible drugs and the interactions or pharmacodynamics between
multiple drugs having structural and functional differences (Voie et al. 2012). At times it is
difficult to differentiate reactions that are immune and non-immune mediated, as the clinical
signs of an allergic reaction is only observable on re-exposure or long lasting exposure to the
drug (Alomar 2014). However recent researches have shown that a prior exposure to the active
component is not a precondition for the onset of a bad drug interaction. To comprehend the
pathophysiology of drug mediated hypersensitive reaction, it is vital to identify few phenomena
such as the T-call sensitization, cross reactivity and antibody sensitization. The drug binds to the
haptens to form complexes of hapten-carrier, which are received by the Antigen presenting cells
(APCs) and are then moved to the lymphoid tissues (Schnyder and Pichler, 2009). The naïve T-
cell recognizes the complexes and sensitization of the T-cells occurs. Apart from the

2DRUG INDUCED HYPERSENSITIVITY REACTION
sensitization of the T- cells, thehapten carrier complex also activates the B-cells to multiply and
differentiate in to plasma cells after which antibodies specific to the drug can be produced
(Aronson 2015).
After the initial sensitization to the drug another set of exposure results in the T- cells and the
antibodies to move into the elicitation phase, related to the type I to IV immune reaction
(Schnyder and Pichler, 2009)..
IgE MEDIATED HYPERSENSITIVITY REACTION (TYPE I)
Drug specific IgE is formed due to the primary drug sensitization and renewed contact
with a small amount of drug might induce drug reactions. This sensitive reaction is reached due
to the presence of the mast cells having high attraction Fc receptors (Schnyder and Pichler 2009).
In order to elucidate a hypersensitive reaction the allergen or the drug should attach to the
antigen binding site within the IgE molecule. Cross linking of two or more allergen binding
region can cause activation of mast cells and the secretion of various inflammatory mediators
like leukotriene, histamine, cytokines and prostaglandins (Hausmann et al. 2012). These
molecules are responsible for increased vascular permeability, bronchoconstriction, increased
production of the mucus contribute the addition of the eosinophil. IgE-mediated reactions can
cause angioedema, urticaria, cardiac complications and severe respiratory symptoms (Hausmann
et al. 2012). The drugs that are responsible for Type I hypersensitivity reaction are mainly the
neuromuscular blocking agents and some drugs like penicillin and cephalosporins.