Cold hives (or urticaria), is a subtype of physical hives that is characterized by the development of hives and swelling in response to cold exposure and rewarming of the skin. It is related to the histamine release of mast cells. Several studies have shown that it is related to IgE and an unknown skin autoallergen that becomes accessible with cold stimulation.
The way it can be diagnosed is with cold provocation tests through application of a cold stimulus (ice cubes, cool packs, cold water baths) to the forearm for 5 minutes and the arms are assessed after 10 minutes. Positive reactions are indicated by the development of hives within minutes of rewarming the skin.
Cold exposure can also lead to a potentially serious and fatal reaction in specific circumstances (jumping into a cold body of water) can lead to anaphylaxis. Some patients may need to carry an injectable epinephrine for those at risk. Reactions can also occur with cold weather, snow, air conditioning, walking down an cold aisle in a supermarket, holding a cold drink or grabbing a cold surface or eating something cold (ice cream).
Besides avoiding the cold, other treatments are available. Non sedating second generation antihistamines and Xolair (omalizumab) are being used to treat cold hives.
Antihistamines such as Clarinex (desloratadine), Xyzal (levocetirizine), Zyrtec (cetirizine), Allegra (fexofenadine), are just some of the few that are used to treat and prevent hives in patients with cold urticaria. Older antihistamines work well too, but they can cause sedation in higher dosages (cyproheptadine, doxepin and hydroxyzine). Cyproheptadine 4mg given 3 times a day, has been shown to completely suppress hive formations in a landmark study of cold urticaria, but other non-sedating antihistamines seem to work just as well.
Xolair (Omalizumab (Xolair) for treating Angioedema and Chronic Hives), given 150mg and 300mg every 4 weeks for 3 consecutive months has also shown positive results for those who antihistamines did not work. There was no significant difference in the 150 or 300mg group.
The side effects of using a non-sedating H1 antihistamine in higher dosages can be; sleepiness, dizziness, headaches, stomach pain and fatigue. Although they are generally well tolerated, most side effects are seen if a 1st generation (sedating) is used.
The biggest takeaway for the treatment of cold hives is that non-sedating antihistamines are effective in the treatment of cold hives in higher than standard doses (up to 4-fold), and updosing does not increase side effects. For treatment resistant patients, Xolair monthly is also effective, although this is an off-label use.