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ALLERGIES

URTICARIA AND ANGIOEDEMA

Diagnostic and Therapeutic Options

By Chris Christodoulou, MD

Urticaria refers to transient, very pruritic lesions that af-
fect up to 20 percent of the population at some point in
their life. They can be divided into acute cases lasting less
than six weeks, and chronic cases lasting more than six
weeks. The acute cases may be associated with an allergic
reaction to a specific factor such as food, medication, insect
bites, etc.(1, 2) In children, viral febrile illness is a frequent
cause of acute urticaria. In contrast to acute urticaria,
chronic urticaria is more commonly idiopathic and in most
cases even extensive laboratory evaluations will not identify
any relevant cause. Autoimmune diseases, malignancies and
infectious etiologies have all been implicated in chronic ur-
ticaria.(3, 4) Urticarial vasculitis is an autoimmune skin lesion
that may look like urticaria but has different features. For
instance, it may last longer, it may resolve with residual
hyper-pigmentation and can be associated with systemic
symptoms.(5)

The urticarial lesions are accompanied by intense itch-
ing, but usually there is no pain. They tend to last less than
24 hours and resolve without any residual hyperpigmenta-
tion. They may involve any part of the body, may appear
at any time of the day or night and they may range in num-
ber from a few lesions to hundreds at any given time and
in size from less than 1 mm to large plaques the size of a
palm.(1, 2, 3)

Angioedema frequently accompanies urticaria and as
long as it does not involve the oral/respiratory tract
(tongue, uvula, throat, lungs) it is not of major concern.
In contrast to the urticaria that usually lasts a few hours,
the angioedema may last up to 48 hours.

The evaluation of urticaria should not be extensive as in
the vast majority of patients there will not be any specific

24 San Antonio Medicine • March 2017