Urticaria, angioedema

Rationale

Urticaria is a common disorder, and if chronic, may result in significant disability. Angioedema, which may coexist with urticaria, may be life threatening if airway obstruction occurs from laryngeal edema or tongue swelling. Both may occur with anaphylaxis.

Causal Conditions

(list not exhaustive)

1. Idiopathic
2. Associated with identifiable causes
   1. Allergic (e.g., drugs, insects, food)
   2. Direct mast cell release (e.g., opiates, radio-contrast agents)
   3. Complement-mediated (e.g., serum sickness, infections)
   4. Physical (e.g., dermatographism, cold)
   5. Other (e.g., mastocytosis, hereditary angioedema)

Key Objectives

Given a patient with urticaria/angioedema, the candidate will diagnose the cause, severity, and complications, and will initiate an appropriate management plan. In particular, the candidate will determine whether the condition is acute and/or life threatening and requires immediate treatment.

Enabling Objectives

Given a patient with urticaria/angioedema, the candidate will

1. list and interpret critical clinical findings, including
   1. elicit a history and physical examination including timing of symptom onset, duration of lesions, and identification of precipitants;
   2. detect the presence of or the risk for serious cardio-respiratory distress or anaphylaxis;
   3. determine chronicity, and possible association with systemic disease;
2. list and interpret critical investigations, including
   1. recognizing that laboratory investigation in both acute and chronic disease is often normal and therefore unnecessary;
3. construct an effective initial management plan, including
   1. determination of the need for emergent/urgent intervention;
   2. identification and discontinuation of offending trigger or pharmacologic agents;
   3. initiation of appropriate medication (e.g., antihistamine, steroids);
   4. prescription of and counselling in use of injectable epinephrine.