By: Theodoros Manfredi
Cold urticaria, also known as 'cold
hives' is an allergy triggered by exposure to the cold which causes red welts to
appear on the skin. These are often itchy and can be accompanied by redness and
swelling in the hands and feet. The hives themselves can vary in size from
around 7mm to 27mm in diameter. Cold urticaria can be congenital or acquired,
and is most likely to occur between the ages of 18-25 in the latter case.
Types
There are various types of cold
urticaria. These include:
Primary Cold Contact Urticaria: Caused
upon contact with windy weather and other cold environments resulting in the
wheal response (a particular type of hive). Can be acquired.
Secondary Cold Contact Urticaria: This is
also characterized by wheals, and is due to serum abnormalities such as
cryoglobulinemia. These are often associated as well with other symptoms such
as Raynaud's phenomenon (a change in color for the fingers or other
extremities) or purpura.
Reflex Cold Urticaria: This is due to
more generalized cooling of the body (rather than being subjected to a cold
environment necessarily).
Familial Cold Urticaria: Of course a
familial genetic condition which results in rash, conjunctivitis and chills
when exposed to cold – or even temperatures just below 22 degrees Celsius. The
condition is mapped to CIAS1.
Symptoms
Hives are caused due to the dilation of
capillaries which enable fluids to flow out into the surrounding tissue. The
body absorbs this fluid resulting in the lumps and redness. Pressing on the
hive often causes the skin to blanch. These hives can last a few minutes or a
few days depending on the person, and often result in a burning or itching
sensation. In rare cases the condition can lead to hypotension which is
potentially life threatening. If the hives appear after less than three minutes
contact with the cold, this suggests the condition is more likely to be
potentially dangerous.
Cause
The cause of the hives is a histamine
reaction that occurs in response to cold stimuli – this might include a drastic
drop in temperature. Cold hives can also be a result of other conditions and it
is often advisable to test for these conditions. A diagnosis can be obtained by
an allergist during which a cold piece of ice is often held against the skin to
test for a reaction.
Treatment
The recommended treatment is simply to
avoid exposure or contact with extreme cold. This means wrapping up warmly and
using wind protective clothing, it also means avoiding swimming in cold water,
and perhaps even moving to a warmer climate. Swimming in particular can be
dangerous as it causes an elevated heart rate and thus increases the chances of
hypotension. Antihistamines may be effective but not always – though
cyproheptadine is often found to be useful, as is ketotifen which prevents mast
cells from discharging histamine. Someone who suffers from cold urticaria might
be advised to consume one of these medications prior to going out on a cold day
or swimming in cool water.
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