Anaphylaxis (Canine) — NAVLE Prep

Quick anchor

Trigger

Sudden collapse after exposure

First step

Epinephrine + shock support

Canine clue

GI signs can dominate

Trap

Do not reach for antihistamines first

Exam core — read this first

Clinical logic → acute exposure pattern plus shock or severe hypersensitivity signs

Immediate drug → epinephrine is the key board answer in severe anaphylaxis

Also treat shock → airway, perfusion, oxygen delivery still matter

Species nuance → dogs often show GI collapse / shock patterns prominently

Pattern recognition

Core pattern

Sudden onsetExposure historyShock / collapse / GI signs

Supporting clues

Vomiting or diarrheaFacial swelling possibleWeak pulsesPale mucous membranesRespiratory compromise in some cases

NAVLE trigger: Canine anaphylaxis is often a circulatory and GI emergency, not just an airway swelling question.

Decision core — what NAVLE actually asks

Severe acute anaphylaxis

→ Give epinephrine and begin stabilization immediately

Shock physiology present

→ Treat perfusion aggressively with standard emergency support

After the crash phase

→ Add adjunctive therapies and continue monitoring for recurrence

Key interpretation

Timing

Acute

Often minutes to hours after trigger

Perfusion

May be poor

Distributive shock pattern

GI signs

Common in dogs

Vomiting / diarrhea may dominate

Respiratory signs

Variable

May occur but are not the only presentation

Blood pressure

Can fall fast

Treat early

History

Critical

Vaccines, stings, drugs, exposures

⚠ Antihistamines are adjuncts. In severe canine anaphylaxis, the board wants epinephrine and shock support first.

Treatment

Step 1

Epinephrine + oxygen / airway and perfusion support

This is the rescue step the exam expects.

Step 2

IV fluids for distributive shock

The patient may be profoundly vasodilated and poorly perfused.

Step 3

Adjunctive antihistamines / glucocorticoids after stabilization

Helpful later, but not the first-line rescue move.

NAVLE traps — where students lose marks

Do not lead with diphenhydramine in the crashing patient

The board answer for severe anaphylaxis is epinephrine.

Canine anaphylaxis can be GI-heavy

Do not dismiss it because airway swelling is not the main feature.

The time course matters

Sudden collapse after exposure is a major clue.

Observe after initial improvement

Recurrence or ongoing shock can still occur.

Differentials — how to separate these on NAVLE

Fast separator: Anaphylaxis is abrupt exposure-related hypersensitivity with shock or severe systemic signs. Compare it with sepsis, hemorrhage, and heatstroke.

Problem	Timing	Trigger	Key separator
Anaphylaxis	Sudden	Exposure	Epinephrine-first logic
Sepsis	Progressive	Infectious source	Needs antibiotics / source control
Hemorrhagic shock	Acute or progressive	Blood loss	No exposure history
Heatstroke	Acute	Heat / exertion	Hyperthermia is key
Hypoglycemia	Variable	Low glucose	Dextrose-responsive neurologic signs

30-second revision

ClueSudden collapse after exposure

First-line drugEpinephrine

Also treatShock and airway / oxygen needs

Dog nuanceGI signs may dominate

Critical trapAntihistamines are adjuncts, not first rescue

Practice questions

Pre-built NAVLE-style · Anaphylaxis

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Q1Recognition

A dog collapses minutes after receiving a known trigger exposure. Which diagnosis is most likely?

Q2First-line therapy

Which therapy is most critical early in severe canine anaphylaxis?

Q3Species pattern

Which statement about canine anaphylaxis is most accurate?

Q4Trap question

What is the best role for antihistamines in severe anaphylaxis?

Q5Differential

Which feature best separates anaphylaxis from sepsis?