Drug Allergies

Question 1

Risk factors

Answer 1

• chemical structure
• Molecular weight
• route of administration
• Dose, duration of therapy, repeated exposure to drug

Question 2

Immunogenic compoud

Answer 2

Hapten/carrier

Question 3

molecular mass required for immunogenicity

Answer 3

greater than 10,000 daltons

Question 4

binding between Hapten and carrier

Answer 4

covalent

Question 5

what must occur for drug to form a hapten/carrier conjugate

Answer 5

be chemically reactive

Question 6

what if the drug is not intrinsically reactive, how can it be activated?

Answer 6

• Biotransformation

- Photoactivation

Question 7

what does complete antigen mean?

Answer 7

macromolecular drugs that do not require binding to invoke an immune response

Question 8

Gell and Coombs classification

Answer 8

I. Anaphylactic - IgE mediated (

Question 9

Fatal anaphylaxis

Answer 9

Asphyxia due to laryngeal edema or cardiovascular collapse

Question 10

Serum sickness

Answer 10

syndrome due to soluble circulating immune complexes (Ag excess)

Question 11

Presents with fever, malaise, lymphadenopathy

Morbilliform skin eruptions

onset is a week - 2 wks post exposure

Answer 11

Serum sickness

• cephalosporins (ceflacor)
• antivenin (equine serum)

Question 12

may be due to release of factors or direct pharmacologic effects on tissues (eg w/ chemo)

High variable temperature pattern (spiking)

prompt resolution after removal of causative drug

Answer 12

Drug fever

Amphotericin B
Antimicrobials

Question 13

Rigors, fever, and hypotension after use of TCN, Doxy, Pen G for treatment of spirochetal and bacterial infections, Louse Borne relapsing fever or Tick borne refractory fever

Answer 13

Jarisch-Herxheimer Reaction

Question 14

JHR happens due to

Answer 14

sudden release of bacterial components from injured and or killed bacteria

Question 15

Drug induced SLE

• drug characteristics?
• Sex distribution?
• Which drugs?
• When does it typically resolve?

Answer 15

• Hydrazine/Amino group linked to an aromatic ring
• Equal
• HIPP: Hydralazine, Isoniazid, procainamide, phenytoin (also quinidine and penicillamine)
• 3-6 mos

Question 16

Onset - several mo after beginning drug

Fever, malaise, rash, Arthralgias, myalgias, mucosal ulcers, pulmonary involvement

Answer 16

Systemic Lupus erythematosus

Question 17

Fever, rash, eosinophilia

proteinuria, hematuria, eosinophiluria

Answer 17

Interstitial Nephritis

• Anti staphylococal PCN
• Cephalosporins
• Sulfonamides
• Cimetidine

Question 18

Mechanisms for Interstitial nephritis

Answer 18

• Humoral: Ab to a drug - basement membrane complex

- Cell mediated

Question 19

Eosinophilia, fever, rash, granulomas on biopsy

• eliminated kidney as the problem

which drugs caused the problem?

Answer 19

Hepatic Hypersensitivity reaction/ toxic hepatitis

• Erythromycin
• PCN

Question 20

How does Hepatic Hypersensitivity reaction/ toxic hepatitis induce autoimmune reaction

Answer 20

• drug acts as a hapten

- may not be inherently toxic to the liver

Question 21

Palpable purpuric lesions

in lower extrimities

Answer 21

Vasculitis

Question 22

Vasculitis is characterized by

Answer 22

inflammation and necrosis of blood vessels

Question 23

Dermatologic reactions - Mild vs Sever. which is common?

Answer 23

Mild is most common

Mild:

• Pruritis
• Maculopapular rash
• Urticaria/Angioedema
• Fixed drug reactions
• Phototoxic

Severe:

• Toxic epidermal necrolysis (TENs)
• Stevens-Johnson Syndrome (SJS)

Question 24

Symmetrical, flat red rash - small confluent bumps
itchy
Begins in back/extremities
Not seen on palms and soles

Answer 24

Maculopapular/Morbilliform Rash

early/late onset depends on sensitization

PCN, antibiotics, anticonvulsants

Question 25

Pruritic, edematous wheals with surrounding erythema Dermatographism

Answer 25

Urticaria/Angioedema

Question 26

Angioedema is found specifically found what type of drug typically causes this issue

Answer 26

facial (esp mouth) and periorbital ACE inhibitors

Question 27

What causes urticaria

Answer 27

Histamine release from mast cells in dermis causing blood plasma to leak out of small BV

Question 28

Common agents that cause Urticaria/Angioedema

Answer 28

Antibiotics, NSAIDs, Anticonvulsants (eg: phenytoin)

Question 29

Dark red or violet lesion that is single or multiple edematous that reappears in the same location if drug is reinitiated

Answer 29

Fixed Drug eruptions

Question 30

Common agents that cause fixed drug eruptions

Answer 30

Antibiotics: PCN, TCN, Cipro, Bactrim | NSAIDs, Quinidine, Sulfonamides

Question 31

Immediately post treatment after short exposure to sunlight

Answer 31

Phototoxicity

Question 32

Activated by long wavelength sunlight - urticarial, eczematous papulovesicular, or exudative eruptions Hapten formed with UV light + drug

Answer 32

Photoallergy

Question 33

Common Agents that cause phototox/allergy

Answer 33

``` TCN Carbamazepine Griseofulvin Coal Tar derivatives OCs ```

Question 34

Topical treatment of preexisting dermatosis causes a new rash to develop. The rash becomes erythematous, indurated, and vesicular

Answer 34

Eczematous Contact Dermatitis

Question 35

Concentric (target) lesions that look like "bulls eye"

Answer 35

Erythema multiforme

Question 36

Severe variant of erythema multiforme

Answer 36

Stevens Johnson Syndrome

Question 37

Mucosal and conjunctival edema High fever, myalgias, arthralgias with conjunctival scarring that can lead to blindness

Answer 37

Stevens Johnson syndrome

Question 38

Common agents that cause stevens johnson

Answer 38

Sulfas Anticonvulsants NSAIDs

Question 39

Erythematous rash that progresses to large flaccid bullae epidermis sloughs and exposes raw dermis - equivalent to 2nd degree burn

Answer 39

Toxic Epidermal Necrolysis | Steven Johnsons that covers more than 30% of the body

Question 40

Most dermatologic rxns are due to

Answer 40

Antibiotics Anticonvulsants NSAIDs

Question 41

scale used for management of ADR

Answer 41

Naranjo Scale

Question 42

Drug induced autoimmunity

Answer 42

- SLE - Hemolytic anemia - Renal interstitial nephritis - Hepatic hypersensitivity

Question 43

Pulmonary reactions

Answer 43

- rhinitis/asthma | - Acute infiltrate/chronic fibrotic pulmonary rxn (Nitrofurantoin)

Question 44

Aplastic anemia is usually seen with

Answer 44

chloramphenicol