Urticaria and Angioedema

A Rational Approach to Diagnosis and Therapy

David H. Dreyfus, MD, PhD


Skin Therapy Letter. 2013;18(1) 

In This Article

Abstract and Introduction


Urticaria and angioedema are common allergic manifestations and some forms of this disorder may be increasing in both prevalence and severity due to changes in medications, environment and other unknown factors. This review focuses on a rational approach to differential diagnosis and therapy of the most common forms of urticaria and angioedema.


Urticaria and angioedema with duration of less than 6–8 weeks is termed acute urticaria.[1–3] In contrast, several forms of chronic urticaria such as physical, autoimmune, and inflammatory urticaria[1–3] usually persist for more than 6–8 weeks. Herein, an algorithmic perspective is offered for the various diagnostic possibilities of chronic urticaria (Figure 1). A checklist for office visits is also included to assist the clinician in formulating a rational approach to diagnosis and therapy of patients presenting with either acute or chronic urticaria (Figure 2).

Figure 1.

Differential diagnosis of urticaria and angioedema ACE = angiotensin-converting enzyme; ANA = antinuclear antibody; C1q = complement protein required for innate immune responses; CD203c = basophil activation marker for allergy detection; IgE = immunoglobulin E antibody; NSAIDs = nonsteroidal anti-inflammatory drugs; TRAPS = TNFRSF1A-associated periodic syndrome

Figure 2.

Checklist for outpatient evaluation of urticaria and angioedema anti-TNF-alpha = anti-tumor necrosis factor-alpha; C1 inh = C1-esterase inhibitor; CBC = complete blood count; FACS = fluorescence-activated cell sorting; HSV = herpes simplex virus; TSH = thyroid-stimulating hormone

Urticaria of less than 6 weeks duration with features indicating progression to a chronic illness should be periodically reevaluated clinically until the diagnosis is clarified. The distinction of 6–8 weeks as a dividing interval between acute and chronic urticaria, while arbitrary, is useful because the most common cause of acute urticaria and angioedema, particularly in children, are transient viral infections.[4–11] Related to this important distinction, acute urticaria and angioedema (in contrast to chronic urticaria/angioedema), can often be associated with a specific cause or trigger.

The terms "acute" and "chronic" do not relate to the severity of urticaria, but only to its duration.[1] Urticaria associated with signs and symptoms affecting organs other than the skin, such as the pulmonary tract (wheezing, cough), gastrointestinal system (vomiting, diarrhea), nervous system (dizziness, loss of consciousness) or cardiac system (changes in blood pressure or heart rate) should be excluded from the diagnosis. Urticaria that is not confined to the skin and associated with any systemic symptoms is more properly termed anaphylaxis, irrespective of the duration or intensity of symptoms.

It is important to exclude anaphylaxis in patients presenting with acute urticaria.[12] Like urticaria, anaphylaxis can be idiopathic or associated with specific triggers such as foods[13,14] or medications.[15] Physicians should consider prescribing epinephrine in patients with urticaria until the diagnosis of anaphylaxis is excluded.[16]