Allergy & Immunology

Question 1

Red Flags for Urticaria

Answer 1

Last >48 hours
Burning
Heal with bruise or scar
Systemic symptoms suggestive of 1) autoimmune dz 2) systemic mastocytosis

Question 2

Treatment Chronic Spontaneous Urticaria (>6weeks)

Answer 2

1) Daily nonsedating anti-histamine (ceterizine)
2) Increase dose (up to 4x recommended)
3) Add LTRA
4) Omalizumab
5) Cyclosporine

Question 3

DDX Chronic angioedema

Answer 3

+Pruritus/urticaria = IgE/mast cell:
-Chronic spontaneous urticaria with angioedema

NO pruritus/urticaria (mast cell OR bradykinin):

a) Acquired:
- ACE/NSAID related (normal C1i/C1i fxn, C4) = Treat ACEi angiodema with icatibant
- Secondary to lymphoproliferative or autoimmune disorder (low C1i/C1i fxn/C4)

b) Hereditary Angioedema (HAE) from c1 esterase deficiency
- Type 1 HAE (low C1i, low C1i fxn, LOW C4)
- Type 2 HAE (N/high C1i, low C1i fxn, LOW C4)
- Type 3 HAE (all normal; NORMAL C4)

Question 4

Definition Anaphylaxis

Answer 4

1) Possible antigen + acute onset skin/mucosal involvement + 1 of (resp distress or HoTN)
2) Likely antigen + >=2 of (skin/mucosal inv, resp Sx, HoTN, GI Sx)
3) Known antigen + acute onset of HoTN (SBP <90 or >30% decrease from baseline)

Question 5

Severe cutaneous adverse drug reactions

-Timeline and causative meds

Answer 5

Acute generalized exanthematous pustulosis (AGEP)

• Within 1 week
• B-lactams

SJS/TEN:

• 1-2 weeks
• ABX (sulfa, pen, cephalosporins, tetracycl, FQ), allopurinol

DRESS:

• 2-6 weeks
• Anti-convulsants, allopurinol, sulfa ABX

Question 6

Management NAC RXNs

Answer 6

1) Flushing only: Continue infusion, no tx

2) Urticaria or angioedema (only 1):
- Stop infusion,
- IM epi + benadryl + steroid,
- Resume infusion at prior rate once symptoms resolve

3) Anaphylaxis:
- Stop infusion,
- IM epi + benadryl + steroid,
- DO NOT RESUME IV NAC (can trial oral)

Question 7

Management monoclonal Ab (ie. ritux) RXNs

Answer 7

Mild (non-life threatening, no resp/BP changes)

• Hold infusion,
• Antihistamine + Tylenol
• Resume @ lower rate when symptoms resolve

Severe/Anaphylaxis:

• Stop infusion,
• Epi + Benadryl + steroid + IV fluids,
• Re-challenge another day with pre-tx

Question 8

10 Immunodeficiency red flags

Answer 8

Family hx of Primary Immunodeficiency

Chronic diarrhea w/ weight loss

Recurrent infections:

• 2+ sinus/ear per year
• 1 PNA per year for 1+ year,
• Req IV abx for infxns
• Fungal, viral infxns (herpes, warts, condyloma, cold), or normally harmless TB like bacteria
• Recurrent deep abscesses

Question 9

Immunodeficiency: type + infxn + w/u

Answer 9

B cells:

• Pyogenic infxns
• Ix: immunoglobulins, vaccination titres, lymphocyte count/subsets

T cells:

• Mycotic + opportunistic
• Ix: lymphocyte count/subsets

Neutrophils:

• Abscess forming infxn w/ low grade pathogens…
• Ix: neutrophil count, Chronic Granulomatous Disease (CGD) Assay

Complements:

• Repeated neisseiria infxns
• Ix: C3, C4, C50

Question 10

CVID (combined variable)

• Pt
• Dx
• Tx

Answer 10

MC symptomatic primary immunodeficiency in adults

Pt: Recurrent sinopulmonary infections

Dx: LOW IgG + LOW IgA or IgM + poor response to vaccination
-Other immunodeficiency causes ruled out (e.g. CLL)

Tx: IVIG or SCIG (sub-cutaneous Immunoglobulin)

Question 11

Anaphylaxis Tx

Answer 11

Epinephrine
H1-Blocker (Ranitidine), 
H2-Blocker (Diphenhydramine), 
Methylprednisolone, 
Glucagon (pt on BB), 
Salbutamol, 
pressors