Hypersensitivity Reaction Flashcards
Most common type of Adverse Drug Eruption
Morbilliform
Ig-E mediated type of hypersensitivity reaction
Type 1. Allergic/Anaphylactic
Cytotoxic type of hypersensitivity reaction
Type 2
Cytotoxic
Immune complexes deposited in small vessels activate complement and recruitment of granulocytes
Type 3.
Immune Complex
Cell-mediated type of hypersensitivity reaction
Type 4.
Delayed Type
Examples of Type 1 Hypersensitivity reaction
Urticaria/Angioedema, anaphylactic shock
Examples of Type 2 Hypersensitivity reaction
Petechiae resulting from thrombocytopenic purpura, drug-induced pemphigus
Examples of Type 3 Hypersensitivity reaction
Vasculitis, urticaria, serum sickness
Examples of Type 4 Hypersensitivity reaction
Fixed drug eruption, Lichenoid eruptions, SJS, TEN
Morbilliform eruptions restricted to a previously sunburned site
UV recall-like reaction
Characteristic features of Drug-induced hypersensitivity syndrome
• Rash developing late (>3 weeks) after the inciting
medication is started; often occurs with the first exposure
to the medication
• Long-lasting symptoms (>2 weeks) after discontinuation
of the causative drug
• Fever (>38°C)
• Multiorgan involvement
• Eosinophilia (>1500 absolute eosinophilia); less common
with dapsone (criteria vary, with some groups citing
counts greater than 1500/μl and others more than
700/μl or above 10% if the leukocyte count is lower than
4000/μl)
• Lymphocyte activation (lymphocytosis, atypical
lymphocytosis, lymphadenopathy)
• Frequent reactivation of HHV-6, HHV-7, EBV, and CMV
7 Drugs implicated in DIHS
- Anticonvulsants: phenobarbital, lamotrigine, and
phenytoin - Long-acting sulfonamides: sulfamethoxazole,
sulfadiazine, and sulfasalazine (but not related
medications—sulfonylureas, thiazine diuretics,
furosemide, and acetazolamide) - Allopurinol
- Nevirapine
- Abacavir
- Dapsone
- Minocycline
TBSA involved in SJS
<10 % TBSA
TBSA involved in TEN
> 30% TBSA
Most common sequalae in SJS/TEN
Ocular scarring and vision loss
Type of ADR which recurs at the same site with
each exposure to the medication.
Fixed Drug Eruption
Multiple monomorphic non follicular pustules with associated fever, facial edema, leukocytosis with neutrophilia (90%) and eosinophilia (30%)
+Nikolsky sign
Acute generalized exanthematous pustulosis
Drug implicated in red man syndrome
Vancomycin
Photodistributed bullous drug hypersensitivity reaction clinically
and histologically resembling porphyria cutanea tarda
Pseudoporphyria
Most frequent cause of pseudoporphyria
Naproxen
Among the three types of pigmentation seen in Minocycline, what produces a blue-black discoloration in areas of prior inflammation?
Type 1- most common
Among the three types of pigmentation seen in Minocycline, what produces a blue-black discoloration on normal skin of anterior shins?
Type 2
Among the three types of pigmentation seen in Minocycline, what produces a generalized muddy brown hyperpigmentation accentuated in sun-exposed areas?
Type 3- least common
Drug implicated in staining of teeth if given during childhood or fetal exposure
Tetracycline
