Antibiotic Allergy

Question 1

Antibiotic allergy in adults

Answer 1

> 90% of drug reactions are NOT immune mediated
15% of adults report allergy actually 5% have one
Risk factors for antibiotic allergy
Previous exposure
Route iv/IMI
Age peaks 20-50
Pros to the onset of symptoms close and just started likely

Question 2

3 types of antibiotic allergy describes

Answer 2

1 immediate 0-1hour IgE mediated anaphylaxis/laryngeal obstruction, urticaria . Hypotension
2 accelerated 1-4hours IgE mediated laryngeal obstruct urticaria wheeze
3 late <72hrs. Non IgE mediated Stephens Johnson syndrome rash neutropenia

Question 3

Diagnosis of antibiotic allergy

Answer 3

1 history 
2 SPT / intradermal applicaiton in a specialist setting so as to be able to resuscitate 
If SPT+ HIGH risk of anaphylaxis 
If SPT -ve low risk of anaphylactic 
3 RAST testing not as Sn/Sp as SPT

Question 4

Penicillin allergy

Answer 4

Most common antibiotic allergy
If proven allergy on SPT consider cross reactivity care
All the ‘cillins’ should be avoided
Cephalosporins care 93-97% people ok

Question 5

Amoxicillin allergy

Answer 5

1 maculopapular non puritic rash common NOT IgE mediated
2 urticarial rash more likely to be IgE mediated and real allergy
Avoid and do SPT

Question 6

Stephens Johnson syndrome

Answer 6

Non IgE mediated
Late reaction
AVOID no challenge

Question 7

Immunodeficiency syndrome 4 characteristic make you consider

Answer 7

Infection increased number hard to respond to antibiotics
Chronic and resistant to treatment chronic
2 specific infection
3 family history of Immunodeficiency syndrome
4 findings on examination
Primary severe combined ID
No t or B cells no thumbs
NSW screening program

Question 8

VCFS

Answer 8

Immunodeficiency recurrent OM/sinuses ent problem speech problems
Cardiac problems low ca++
Anatomical problem small mid face +/- cleft palate

Question 9

Neutrophil def

Answer 9

Gingivitis
LN in neck
Deep skin infection

Question 10

Recurrent infection in one site suggest anatomical problem there

Answer 10

Skin eg eczema HSV/Staph/strep
Resp CF/ASthma FB/ primary immobile cilia
Urinary tract unusual in immunodeficiency malformation

Question 11

Screening for immunodeficiency

Answer 11

Fbc and film

IgG.A M E these two tests will pick up most primary ID