Face swelling and whole body pruritus
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anaphylaxis angioedema management
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Face Swelling + Whole-Body Pruritus (Itching)
The combination of facial swelling (angioedema) and whole-body pruritus (itching) is a classic presentation of a systemic hypersensitivity reaction. The most important diagnosis to consider first is anaphylaxis, which is life-threatening.
Pathophysiology
These symptoms arise from mast cell and basophil degranulation, releasing histamine, tryptase, prostaglandins, and leukotrienes. Histamine causes:
- Vasodilation and increased vascular permeability (swelling/angioedema)
- Sensory nerve stimulation (pruritus)
- Smooth muscle contraction (bronchospasm, GI cramps)
Differential Diagnosis
| Condition | Key Features |
|---|---|
| Anaphylaxis (IgE-mediated) | Acute onset; may have respiratory distress, hypotension; triggered by food, drug, insect sting |
| Allergic urticaria + angioedema | Hives + facial/lip swelling; without systemic compromise |
| Hereditary angioedema (HAE) | Recurrent angioedema; NO urticaria/pruritus; C1-esterase inhibitor deficiency |
| ACE inhibitor-induced angioedema | Drug history; bradykinin-mediated; no pruritus |
| Drug reaction / DRESS | Widespread rash + systemic involvement |
| Mastocytosis | Recurrent episodes; urticaria pigmentosa on skin |
| Carcinoid syndrome | Flushing, diarrhea; elevated urinary 5-HIAA |
"A history of sudden urticarial rash accompanied by respiratory difficulty, abdominal pain, or hypotension, strongly favors the diagnosis of anaphylaxis." - Rosen's Emergency Medicine
Signs & Symptoms of Anaphylaxis by System
From Tintinalli's Emergency Medicine:
| System | Findings (approximate incidence) |
|---|---|
| Skin | Urticaria and/or angioedema (60-90%), flushing (45-55%), pruritus only (2-5%) |
| ENT | Oropharyngeal/throat fullness (50%), tongue swelling (1-2%), uvular edema (1-5%) |
| Respiratory | Shortness of breath/wheezing (45-50%), pharyngeal/laryngeal edema (50-60%) |
| Cardiovascular | Hypotension (30-35%), chest pain (4-5%) |
| GI | Nausea, vomiting, cramps, diarrhea (25-30%) |
Common Triggers (Causes)
From Goldman-Cecil Medicine:
- Drugs: Antibiotics (penicillins, cephalosporins, sulfonamides), NSAIDs, opiates, radiocontrast dyes, aspirin, ACE inhibitors
- Foods: Shellfish, nuts, eggs, milk, berries, soy
- Insect stings/bites: Hymenoptera (bees, wasps)
- Blood products: RBCs, platelets, immunoglobulins
- Environmental: Latex, animal dander, exercise
- Vaccines
Immediate Management
STEP 1 - Assess ABC (Airway, Breathing, Circulation)
This is the top priority. If angioedema is producing respiratory distress, intubate early - delay risks complete airway obstruction.
STEP 2 - First-Line Therapy
Epinephrine (adrenaline) is the ONLY first-line drug. There are NO absolute contraindications in anaphylaxis.
| Route | Adult Dose | Pediatric Dose |
|---|---|---|
| IM (vastus lateralis/thigh - preferred) | 0.3-0.5 mg (1:1000 solution) | 0.01 mg/kg, max 0.5 mg |
| IV (only if cardiovascular collapse) | Dilute; continuous infusion | Same principle |
| EpiPen (autoinjector) | 0.3 mg adult | 0.15 mg if <30 kg |
- Repeat IM dose every 5-10 minutes if no improvement
- Thigh injections provide higher and faster peak epinephrine levels than deltoid
- Place patient in supine/recumbent position
- IV crystalloids (0.9% NS) for hypotension: 1-2 L adult, 20 mL/kg pediatric
STEP 3 - Second-Line Therapy (adjuncts, NOT replacements for epinephrine)
"Antihistamines and corticosteroids are second- and third-line agents and should NOT replace or precede epinephrine." - Rosen's Emergency Medicine
| Drug | Role | Dose |
|---|---|---|
| H1 antihistamine (diphenhydramine/cetirizine) | Reduces pruritus, urticaria | Diphenhydramine 25-50 mg IV/PO |
| H2 antihistamine (ranitidine/famotidine) | Additive antihistamine effect | Ranitidine 50 mg IV |
| Corticosteroids (methylprednisolone/prednisone) | Prevent biphasic reaction | Methylprednisolone 1-2 mg/kg IV |
| Inhaled beta-agonist (albuterol) | Bronchospasm | 2.5 mg nebulized |
| Glucagon | For patients on beta-blockers | 1-2 mg IV |
For Refractory Anaphylaxis:
- IV epinephrine infusion (0.1-1 mcg/kg/min)
- Consider vasopressors (norepinephrine, vasopressin)
Special Case: Hereditary Angioedema (HAE)
HAE is bradykinin-mediated (not histamine-mediated), so epinephrine and antihistamines have limited effect. It presents as:
- Recurrent angioedema of face, lips, extremities, genitalia, GI tract
- No urticaria or pruritus (key distinguishing feature)
- Low C4 and reduced C1-esterase inhibitor levels on lab testing
Specific HAE treatments:
- Icatibant (bradykinin B2 receptor antagonist)
- Ecallantide (plasma kallikrein inhibitor)
- C1-esterase inhibitor concentrate (human or recombinant)
- Fresh frozen plasma (FFP) as an alternative
Observation & Discharge
- Observe all patients for at least 4-6 hours (risk of biphasic anaphylaxis - recurrence 4-12 hours later)
- Admit if: protracted anaphylaxis, hypotension, airway involvement, unknown trigger, needed IV epinephrine
- On discharge:
- Prescribe self-injectable epinephrine (EpiPen)
- Written emergency action plan
- Refer to allergist/immunologist
- Medical alert bracelet
- Avoid confirmed triggers
Sources: Rosen's Emergency Medicine; Tintinalli's Emergency Medicine; Goldman-Cecil Medicine; Washington Manual of Medical Therapeutics
Which blood tests to be done
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Here is a structured breakdown of blood tests - organized by when and why:
Blood Tests for Face Swelling + Whole-Body Pruritus
Phase 1 - Acute Setting (Emergency / ED)
"Laboratory investigations are of minimal utility and should be limited in the ED setting." - Tintinalli's Emergency Medicine
Do NOT delay treatment to run tests. Labs in the acute phase are mainly for confirmatory or safety purposes.
| Test | Why | Timing / Notes |
|---|---|---|
| Serum Tryptase | Confirms mast cell degranulation (anaphylaxis) | Draw within 1-3 hours of onset - elevated for several hours. Poor sensitivity: ~1/3 of true anaphylaxis cases have a normal level. Gold standard is a baseline tryptase drawn >24 hours later to compare |
| Serum Histamine | Marker of mast cell activation | Only elevated 5-30 minutes after reaction - almost always normal by ED arrival; rarely useful in practice |
| ABG (Arterial Blood Gas) | If respiratory distress or hypoxia present | Assess oxygenation, pH |
| FBC/CBC | Baseline; look for eosinophilia (allergy/parasites) | Useful if unsure of diagnosis |
| Renal function (U&E/BMP) | Pre-fluid resuscitation baseline | If haemodynamically compromised |
| Blood glucose | Rule out hypoglycaemia mimicking collapse | Quick bedside test |
Phase 2 - Post-Acute Workup (Outpatient / Follow-up)
Once the patient is stabilised, blood tests help identify the cause and rule out serious underlying conditions.
A. Allergy / Immunology Panel
| Test | What it detects | Indication |
|---|---|---|
| Total serum IgE | Elevated in atopic individuals | Baseline for all suspected allergic reactions |
| Specific IgE (RAST / ImmunoCAP) | Allergen-specific antibodies (food, drug, venom, latex, etc.) | Identify the exact trigger - test only for suspected allergens |
| Serum tryptase (baseline) | Resting elevated tryptase suggests mastocytosis | Drawn >24h after reaction; elevated baseline points to systemic mastocytosis |
B. Complement / Angioedema Panel
(Especially if: recurrent angioedema, NO urticaria/pruritus, poor response to antihistamines)
| Test | Finding | Interpretation |
|---|---|---|
| C4 level | Low (even between attacks) | Most sensitive screen for HAE types I and II and acquired angioedema |
| C1 esterase inhibitor antigen (C1-INH protein level) | Low in HAE type I | Deficient protein production |
| C1 esterase inhibitor function | Low in HAE type II | Protein present but non-functional |
| C1q level | Low only in acquired angioedema | Distinguishes acquired from hereditary (C1q is normal in HAE) |
| C3 level | Usually normal in HAE; low in acquired | Complement pathway involvement |
"The key to diagnosis is the direct measurement, especially during an attack, of C1 esterase inhibitor protein (antigen test) and function, as well as levels of C4." - Goldman-Cecil Medicine
Interpretation summary:
| Condition | C4 | C1-INH protein | C1-INH function | C1q |
|---|---|---|---|---|
| HAE Type I | Low | Low | Low | Normal |
| HAE Type II | Low | Normal | Low | Normal |
| Acquired angioedema | Low | Low | Low | Low |
| ACE inhibitor-induced | Normal | Normal | Normal | Normal |
| Histaminergic angioedema | Normal | Normal | Normal | Normal |
C. Autoimmune / Systemic Workup
(For chronic or recurrent urticaria lasting >6 weeks)
| Test | What it detects |
|---|---|
| ANA (Antinuclear antibodies) | SLE, connective tissue disease |
| Anti-thyroid antibodies (anti-TPO, anti-thyroglobulin) | Autoimmune thyroid disease (Hashimoto's) - associated with chronic urticaria |
| TSH / Free T4 | Thyroid dysfunction as a trigger |
| ESR / CRP | Systemic inflammation; vasculitic urticaria |
| Serum protein electrophoresis (SPEP) | Monoclonal gammopathy / lymphoma (especially if acquired angioedema, age >40) |
| IgG/IgM/IgA levels | Immunodeficiency or dyscrasia |
D. Rule Out Infectious / Parasitic Triggers
| Test | Rationale |
|---|---|
| FBC with differential | Eosinophilia suggests parasitic infection, drug reaction, atopy |
| Hepatitis B & C serology | Viral hepatitis is a known urticaria trigger |
| H. pylori serology or stool antigen | Associated with chronic urticaria in some patients |
| Stool microscopy for ova & parasites | If tropical/endemic exposure or persistent eosinophilia |
E. Exclude Malignancy (if acquired angioedema suspected)
| Test | Target |
|---|---|
| LDH, uric acid | Lymphoma screen |
| SPEP + immunofixation | Plasma cell dyscrasia |
| Flow cytometry / bone marrow | If systemic mastocytosis suspected (elevated baseline tryptase >20 ng/mL) |
Quick Summary Table
| Phase | Priority Tests |
|---|---|
| Acute (ER) | Serum tryptase (within 1-3h), CBC, metabolic panel, ABG if needed |
| Allergy follow-up | Total IgE, specific IgE (ImmunoCAP), baseline tryptase |
| Angioedema workup | C4, C1-INH antigen + function, C1q, C3 |
| Chronic urticaria | TSH, anti-TPO, ANA, ESR/CRP, hepatitis serology |
| Suspected mastocytosis | Baseline serum tryptase (>20 ng/mL is significant) |
| Acquired angioedema | C1q, SPEP, LDH (exclude lymphoma) |
Sources: Tintinalli's Emergency Medicine; Goldman-Cecil Medicine
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