12
Cholinergic Urticaria
Î Patients with cholinergic urticaria have hives that are ''pinpoint''
(1–3 mm) and surrounded by large flares in association with an
increase in core body temperature. (B)
Î Common provoking factors for cholinergic urticaria include exercise,
sweating, emotional factors, and hot baths or showers. (B)
Î Provocative challenges that increase core body temperature, such
as exercise and hot water immersion or methacholine intradermal
challenge have been considered for the diagnosis of cholinergic
urticaria. However, the negative predictive value of these tests is not
optimal, and lack of response cannot rule out the diagnosis. (D)
Î The severity of cholinergic urticaria ranges from mild pruritus to
serious and potentially life-threatening reactions. (C)
Cold Urticaria
Î Patients with cold urticaria have pruritus and swelling with exposure
of the skin to a cold stimulus. Patients with cold urticaria can have
systemic reactions associated with systemic cold exposure
(e.g., aquatic activities). (B)
Î The diagnosis of cold urticaria can be confirmed by applying a cold
stimulus (e.g., an ice cube on the forearm) to the patients' skin and
observing a wheal-and-flare reaction during rewarming of the skin.
Some forms of cold urticaria might have a negative ice cube test
result. (B) The primary treatment for cold urticaria is avoidance of
cold exposure, as feasible; however, prescribing pharmacotherapy is
also frequently advisable. (C)
Delayed Pressure Urticaria/Angioedema (DPUA)
Î Patients with DPUA have swelling (which can be painful) with a delay of
4-6 hours after exposure of the skin to a pressure stimulus. In some
cases the delay can be as long as 12 or even 24 hours after pressure
exposure. Common provoking factors include working with tools,
sitting on a bench, or wearing constricting garments. (B)
Î DPUA can be confirmed by a challenge with 15 lbs of weight suspended
over a patient's shoulder for 10 or 15 minutes. Development of
angioedema in a delayed fashion at the site of pressure is considered
a positive challenge result. (C)
Î Management of DPUA differs from other types of CU/angioedema and is
often very difficult to treat. Additional pharmacotherapeutic treatment
is frequently required, along with avoidance measures. Conventional
antihistamine dosing frequently lacks efficacy for achieving control of
symptoms. (C)
Acute, Chronic and Physical Urticaria
and Angioedema
