Key Points
2
Î Acute urticaria and angioedema are differentiated from chronic
urticaria (CU) based on the duration of illness. Urticaria and
angioedema with duration of <6 weeks is termed acute urticaria.
Î If urticaria of <6 weeks' duration has features suggesting it might
progress to a chronic illness, such patients should be periodically
re-evaluated until a diagnosis is clarified.
Î Acute urticaria and angioedema should be differentiated from
anaphylaxis.
• Urticaria/angioedema associated with signs and symptoms in organs other than
the skin, such as the pulmonary tract (wheezing and cough), gastrointestinal
system (vomiting and diarrhea), nervous system (dizziness and loss of
consciousness), or cardiac system (changes in blood pressure or heart rate),
can occur in patients with anaphylaxis.
Î Epinephrine should be prescribed if the diagnosis of anaphylaxis
has not been excluded.
Acute Urticaria and Angioedema
Î Acute urticaria and angioedema are differentiated from chronic
urticaria and angioedema (CUA) based on duration of illness. (D)
Î Acute urticaria and angioedema should be differentiated from
anaphylaxis. (D)
Î Acute urticaria and angioedema are often but not always related
to mast cell and basophil activation from multiple triggers, which
include IgE- and non–IgE-mediated mechanisms. (LB)
Î Acute urticaria and angioedema are more frequently associated
with identifiable conditions. When this disorder becomes chronic,
it is less likely to be associated with an identifiable cause. (D)
Î Although skin biopsy is not indicated in most cases of acute urticaria
and angioedema, it might occasionally be useful for differentiating
this condition from other inflammatory disorders. (C)
Î Common causes of acute urticaria and angioedema, including
medications and foods, should be identified by a detailed history
and eliminated, if possible. (C)
Acute, Chronic and Physical Urticaria
and Angioedema
