Your next patient is 28 and developed swelling and wheeze 15 minutes after eating. Here's how the anaphylaxis case unfolds and what to pick up on the way.

An anaphylaxis case can be misread as simple urticaria, asthma or panic when the first thing the learner hears is hives, wheeze and a tight throat minutes after dessert. The rapid onset after eating, hoarse voice and feeling faint can be brushed off or split into separate problems.

You hear: "Sudden swelling and wheeze that came on after eating." This page walks through how this case presents in the moment, the key timeline and symptom clusters to pick up in the history, the bedside findings and the tests, and the teaching points on diagnosis and observation. It is framed by a 28 year old with widespread itchy hives and flushing, lip and tongue swelling, wheeze, shortness of breath and worsening throat tightness minutes after likely nut exposure in a known nut allergy.

How the case presents

Your next patient is 28 and developed swelling and wheeze 15 minutes after eating. In their own words: "Sudden swelling and wheeze that came on after eating."

Observations on arrival:

Observation	On arrival
Heart rate	124 beats per minute
Blood pressure	86/52 mmHg
Respiratory rate	28 breaths per minute
Oxygen saturation	91%
Temperature	36.7 °C

What to pick up in the history

These are the findings the case is built around. Each one moves you towards or away from anaphylaxis, and the scorecard checks whether you found it.

Widespread itchy hives and flushing minutes after eating: skin and mucosal change with sudden onset after an allergen is a core anaphylaxis criterion.
Lip and tongue swelling with tight throat and hoarse voice: laryngeal angioedema is the Airway problem that makes this anaphylaxis rather than a simple allergic rash.
Wheeze and shortness of breath: the Breathing component of anaphylaxis; bronchospasm confirms a life-threatening reaction.
Feeling faint and light-headed: suggests the Circulation problem of vasodilatation and hypotension, indicating evolving shock.
Known nut allergy and the dessert almost certainly had nuts: identifies the trigger, raises pre-test probability enormously and dictates immediate allergen avoidance.
Feels his throat is closing and breathing is getting harder.
Everything began within minutes of eating: sudden onset minutes after exposure separates anaphylaxis from other causes of wheeze or collapse.

Red flags you must not miss

The case marks these as must-elicit. They only come out if you ask.

Feels his throat is closing and breathing is getting harder.
He has no chest pain at all, nothing that spreads to the arm or jaw.

Investigations and what they showed

Tryptase: Serial mast-cell tryptase: raised at presentation (and at ~1 to 2 hours), falling towards a normal baseline after 24 hours.
Peak flow (bedside): Markedly reduced, bronchospasm.
Inspect the skin: Widespread raised pale-centred weals (hives) on erythematous skin, blotchy and confluent across the trunk, they came up within minutes of the meal. Why it helps: urticaria is the skin/mucosal component that, together with airway, breathing or circulation compromise after an allergen, defines anaphylaxis, but on its own it is the dangerous under-call.
Inspect the upper limbs: Raised, itchy urticarial weals over the inner upper arm, confirming that the eruption is generalised rather than localised. Why it helps: shows the rash is truly generalised, a systemic mast-cell reaction, not a contact or local reaction.
Inspect the face: Diffuse non-pitting swelling of the face in a young man, puffy cheeks and jawline with loss of the normal facial contours and narrowed eye openings.
Inspect the tongue: A grossly swollen tongue that fills the mouth and protrudes between the lips, too large to retract, he cannot swallow and his voice is hoarse.
Inspect the lips: Both lips are tensely swollen and everted, with pouting non-pitting oedema that distorts the vermilion border. Why it helps: lip angio-oedema is often the first visible warning that the same swelling is developing in the pharynx and larynx.
Inspect the work of breathing: He is visibly struggling: respiratory rate 28, using accessory muscles with tracheal tug and intercostal recession, an audible expiratory wheeze and inspiratory stridor, and he can only speak in short broken sentences.
Inspect the patient's colour: Flushed, deeply red skin over the face, neck and upper chest, with cool clammy peripheries and dusky lips as the hypoxia and hypotension worsen. Why it helps: flushing reflects massive histamine-driven vasodilatation, the same vasodilatation causing the BP of 86/52; a shocked, hypotensive patient must be laid flat with the legs raised, never sat bolt upright.
Inspect the patient's level of alertness and demeanour: Awake but frightened and restless, gripping the trolley, with a sense of impending doom and repeatedly saying his throat is closing. Why it helps: A sense of impending doom and agitation are recognised features of anaphylaxis; increasing drowsiness would signal imminent collapse.
Inspect the neck veins (JVP): The neck veins are flat and the JVP is not visible even with the patient laid flat.

Imaging findings

12-lead ECG: Sinus tachycardia, no acute ischaemic changes. Normal.
X-ray chest: Clear lung fields, no pneumothorax or consolidation. Normal.

Why the diagnosis is anaphylaxis

The decisive diagnosis is anaphylaxis (food-induced), a sudden (minutes) onset, after a likely nut exposure, of a life-threatening Airway problem (lip/tongue/throat swelling, hoarse voice, stridor), Breathing problem (wheeze, hypoxia) and Circulation problem (hypotension, tachycardia), together with skin/mucosal changes (urticaria, angioedema, flushing). Distinguish it from acute severe asthma, a vasovagal faint, septic shock, non-allergic (ACE-inhibitor/hereditary) angioedema and a panic attack.

Anaphylaxis at a glance

What it is

Anaphylaxis is a sudden, severe allergic reaction that develops within minutes of exposure to a trigger, usually a food, a drug, or an insect sting. It is a clinical diagnosis: a life-threatening problem with the Airway, Breathing or Circulation, usually together with skin or mucosal changes such as urticaria, angioedema, or flushing.

Pathogenesis

In someone previously sensitised, the allergen binds IgE antibodies on mast cells and basophils, triggering them to degranulate and release histamine and other vasoactive mediators throughout the body. This causes widespread vasodilation and increased vascular permeability (leading to angioedema, urticaria and hypotension), smooth muscle constriction in the airways (wheeze and stridor), and swelling of the lips, tongue and throat that can rapidly compromise the airway.

Who it affects

Anaphylaxis can affect anyone with a significant allergy, and risk is highest in those with known food, drug or insect-venom allergies, asthma, or a previous anaphylactic reaction.

How serious it is

Anaphylaxis is immediately life-threatening: the airway can occlude within minutes from laryngeal angioedema, and circulatory collapse can follow rapidly.

Causes and risk factors

A personal history of atopy, asthma, or a previous anaphylactic episode raises the risk of a severe reaction.

Investigations and lab tests

Specific-IgE or allergen testing belongs in the allergy clinic afterwards, not in the emergency setting.

At a glance: Supports the diagnosis afterwards: serial mast-cell tryptase. Allergy clinic later: specific-IgE/allergen testing.

Teaching points

Anaphylaxis is a clinical diagnosis: a sudden onset (usually minutes) after an allergen of a life-threatening Airway and/or Breathing and/or Circulation problem, usually with skin/mucosal changes (urticaria, angioedema, flushing).
Remove/stop the trigger where possible.
Confirm retrospectively with serial mast-cell tryptase (timed samples); specific-IgE/allergen testing is for the allergy clinic later, not the acute setting.
Observe for a biphasic reaction before discharge (a monitored period), as symptoms can recur hours later.

Practise a similar case

On the page, it is obvious that hives, lip swelling and wheeze 15 minutes after a nut dessert point one way. In the room, picking up a hoarse voice and pinning down that timeline while the clock ticks is harder. Test yourself with the next simulated patient and see how your questioning holds up.

Here's one from the same specialty, with the diagnosis left for you to find. Your next patient has chest pain after falling off a ladder 1 hour ago. Take this patient's history in Diagnosica. It's free to start, no card needed.

Anaphylaxis case presentation: history, findings and tests