Cold Urticaria (Cold Hives)

What happens in cold urticaria

When skin is cooled and then rewarms, mast cells in the skin release histamine and other chemicals. These make small blood vessels leak, producing raised, itchy welts (wheals). In more extensive reactions, the chemicals enter the bloodstream and can lower blood pressure, causing a systemic reaction similar to anaphylaxis.

Cold urticaria is one of the "inducible" types of chronic urticaria, where hives are reliably triggered by a physical stimulus.

Types

• Primary (idiopathic) acquired cold urticaria: the most common type, with no underlying cause found. It often follows a viral infection.
• Secondary cold urticaria: linked to another condition, such as cryoglobulinemia (proteins that clump in the cold), hepatitis C, infectious mononucleosis, HIV, or blood cancers. Uncommon.
• Familial cold autoinflammatory syndrome: a rare inherited condition causing rash, fever and joint pain after general cold exposure. It does not respond to antihistamines and needs specialist treatment.

Symptoms

• red, itchy welts (hives) on skin exposed to cold, appearing within minutes and often worse as the skin warms
• swelling of the hands after holding cold objects
• lip or mouth swelling (angioedema) after cold drinks or ice cream
• burning sensation
• in widespread reactions: headache, flushing, fast heartbeat, dizziness, fainting and wheezing

Reactions usually last 30 minutes to 2 hours. This differs from chilblains, which appear hours after damp cold and last weeks, and from Raynaud's phenomenon, where fingers change color without hives. The most serious reactions happen when a large area of skin is cooled at once, as in swimming in cold water, which has led to drowning.

Diagnosis

• Ice cube test: an ice cube in a plastic bag is placed on the forearm for up to 5 minutes. A raised, itchy welt in the shape of the cube within 10 minutes of removal confirms cold urticaria. A false negative is possible.
• TempTest device: a device that tests a range of temperatures to find the threshold that triggers hives, which helps guide avoidance and treatment.
• Blood tests: blood count and inflammatory markers; cryoglobulins and infection tests if a secondary cause is suspected.

Stop antihistamines for several days before testing if your doctor advises.

Treatment

Avoid sudden cold

• Test water before swimming; never swim alone; avoid cold lakes and the ocean if your reactions are severe.
• Dress warmly and cover exposed skin in cold weather.
• Avoid ice-cold drinks and foods if you get mouth or throat swelling.
• Warm up gradually after cold exposure.
• Tell your surgical team, as cold IV fluids and operating rooms can trigger reactions.

Medicines

• Non-drowsy antihistamines (such as cetirizine, loratadine, fexofenadine) taken daily or before expected cold exposure. Doctors often increase the dose up to 4 times the standard dose under medical supervision when needed.
• Omalizumab, an injected biologic, can help people who do not respond to high-dose antihistamines.
• Epinephrine auto-injector: prescribed for people who have had systemic reactions. Carry it at all times, especially near water.
• Other options: short courses of antibiotics or other treatments are sometimes tried in resistant cases under specialist care.

Outlook

Cold urticaria often improves over time. Many people find their symptoms ease or resolve within about 5 to 6 years, though some have it for longer. Reactions can be controlled well with antihistamines and sensible precautions.

Frequently asked questions

What triggers cold urticaria?

Cold air, wind, cold water, cold objects, and cold foods and drinks can all trigger it. Hives appear in the areas exposed to cold, usually as the skin rewarms. Swimming in cold water is the most dangerous trigger because it cools a large area of skin at once.

Is cold urticaria dangerous?

Usually not, but it can be. Large exposures such as swimming in cold water can cause a whole-body reaction with fainting, low blood pressure and breathing problems. People with severe reactions should carry an epinephrine auto-injector and avoid swimming alone.

How do you test for cold urticaria?

The ice cube test is the standard test. An ice cube in a plastic bag is held on the forearm for up to 5 minutes. A raised welt shaped like the ice cube developing within about 10 minutes confirms the diagnosis.

Does cold urticaria go away?

Often, yes. Many people find their symptoms fade over several years, though the course varies. Antihistamines, avoiding sudden cold exposure and, if needed, omalizumab keep symptoms under control in the meantime.