Patient awoke Saturday with lip edema; what is the appropriate initial management?

Management of Acute Lip Swelling

For a patient with isolated lip swelling since Saturday, immediately assess for airway involvement and administer intramuscular epinephrine 0.3 mg, IV diphenhydramine 50 mg, IV methylprednisolone 125 mg, and an H2-blocker, as this presentation suggests histamine-mediated angioedema until proven otherwise. 1

Immediate Airway Assessment (First Priority)

• Evaluate immediately for voice changes, difficulty swallowing, stridor, or respiratory distress, as angioedema can progress unpredictably to involve the oropharynx and larynx, even with isolated lip involvement 1, 2
• Position the patient upright and apply high-flow oxygen if any signs of airway compromise are present 2
• Laryngeal involvement carries approximately 30% historical mortality and requires continuous monitoring in a facility capable of emergency intubation 2

Determine Angioedema Type

• Check immediately for the presence or absence of urticaria (hives) and itching to distinguish histamine-mediated from bradykinin-mediated angioedema 1, 3
• Urticaria is present in approximately 50% of histamine-mediated cases and strongly suggests allergic angioedema 1, 3
• Ask specifically about ACE inhibitor use, as ACE inhibitor-induced angioedema accounts for 30-40% of emergency department presentations and will NOT respond to standard allergy treatments 4

Initial Pharmacologic Treatment

For Presumed Histamine-Mediated Angioedema (with urticaria/itching):

• Epinephrine 0.3 mg intramuscularly (0.3 mL of 1:1000 solution) - this is first-line therapy 1, 2, 5
• Diphenhydramine 50 mg IV 1
• Methylprednisolone 125 mg IV 1
• Ranitidine 50 mg IV or famotidine 20 mg IV (H2-blocker) 1

For Bradykinin-Mediated Angioedema (no urticaria, on ACE inhibitor, or non-responsive to above):

• Discontinue ACE inhibitor permanently if applicable 1
• Icatibant 30 mg subcutaneously OR plasma-derived C1-inhibitor concentrate 1000-2000 units IV 1, 2
• Do NOT use epinephrine, antihistamines, or corticosteroids - these are completely ineffective and delay appropriate therapy 2

Observation and Monitoring

• Observe for at least 2-4 hours after symptom resolution for patients with mild symptoms who respond to treatment 1
• Monitor for biphasic reactions, which can occur up to 6 hours after initial presentation 1
• Any oropharyngeal involvement mandates prolonged observation in a facility capable of airway management 1, 2

Common Pitfalls to Avoid

• Do not assume isolated lip swelling is benign - airway progression can be unpredictable and rapid 1, 2
• Do not treat bradykinin-mediated angioedema with standard allergy medications - this wastes critical time and provides no benefit 2
• Do not discharge without ensuring complete symptom resolution and providing emergency action planning 1

Discharge Planning (Only After Symptom Resolution)

• Prescribe an epinephrine auto-injector for future episodes 1
• Provide written emergency action plan 1
• Document permanent contraindication to all ACE inhibitors if ACE inhibitor-induced angioedema was diagnosed 1
• Arrange allergy/immunology follow-up for identification of triggers 3

Alternative Diagnoses to Consider

• Orofacial granulomatosis if recurrent episodes fail to respond to antihistamines and present with persistent lip enlargement 6
• Allergic contact dermatitis if erythema, warmth, and tenderness are present 7
• Infection (cellulitis/abscess) if fever, erythema, and localized tenderness are present 2