Cold-Induced Allergies: Myth or Reality?

There is indeed an allergy to cold; it is also called cold urticaria. Cold allergy was first described in 1866. Now it affects 0.05% of the world’s population. Cold urticaria manifests itself as an itchy rash and edema of the skin. It occurs most frequently in young and middle-aged people, and in women twice as often as in men.

What is an allergy to cold

Cold urticaria is a rare form of chronic-induced urticaria. Urticaria is a condition in which the skin is swollen and red, with itchy blisters that can be white or red.

Induced urticaria is caused by a known exposure, such as contact with something like cold air, water, or objects.

The exact mechanism of development of an allergic reaction to cold has not yet been established.

In urticaria, symptoms occur when mast cells, a type of immune cell, become activated. This usually happens because the immune system reacts to a specific allergen.

On the surface of the mast cells are receptors for immunoglobulin E (IgE) molecules, which are antibodies that the immune system cells produce when an allergen enters the body. IgE molecules bind to mast cell receptors and reside on their surface.

When the allergen re-enters the body, its molecules attach to the IgE molecules, the mast cells are activated and release histamine and other inflammatory mediators. As a result, blood vessels dilate, the skin becomes red, and swollen, and blisters appear.

But in cold urticaria, no allergen enters the body. There is an assumption that under the influence of low temperature, autoallergens are formed in the skin, resulting in the activation of mast cells.

How cold urticaria manifests itself

Symptoms of cold urticaria develop within about five minutes of exposure to low temperatures and usually last for several hours.

The main symptoms are an itchy rash and angioedema, which affect cold-affected parts of the body. In rare cases, a generalized form of urticaria develops, with blisters spreading all over the body.

Even rarer in cold allergies is anaphylactic shock. In this case, in addition to the usual local symptoms develop respiratory edema with difficulty in breathing, and blood pressure drops.

Anaphylactic shock can be fatal if first aid is not provided in time. More often severe reactions develop when immersed in cold water – e.g. winter swimming.

How cold allergies are related to other conditions

Cold urticaria can be primary or secondary.

Primary cold urticaria occurs on its own, as a separate disease. However, people with cold allergy often have other allergies, such as allergic rhinoconjunctivitis and bronchial asthma.

A third of patients with cold urticaria is diagnosed with other forms of urticaria, such as cholinergic, in which symptoms occur in response to sweating.

Secondary cold urticaria develops against the background of some blood diseases or infections. For example, people with leukemia, lymphosarcoma, viral hepatitis, and syphilis may have such symptoms. Cold allergy can be against the background of the usual acute respiratory infections or chickenpox.

There is also a hereditary disease in which there are symptoms similar to the usual cold urticaria. This is a familial cold inflammatory syndrome or FCAS. In this disease, after general hypothermia, in addition to a rash on the skin, there is a fever and pain in the joints.

The skin rash may resemble urticaria but usually looks a little different: not blisters, but pale pink or red spots. Also, the rash is usually not itchy, although it may be associated with other sensations: burning, tightness, and tingling of the skin.

An important difference between FCAS and cold urticaria is that contact of the skin with something cold is not enough to cause symptoms – you need a general cooling of the body, such as a walk in the cold air in unsuitable clothing.

How cold allergies are diagnosed

Cold urticaria is diagnosed on the basis of provocation tests. The simplest and most common is an ice cube test. It is placed on a person’s forearm for 1-5 minutes.

In cases of cold allergy, a noticeable red rash and swelling will appear where the ice comes into contact with the skin within a few minutes. With hereditary cold syndrome, the test will be negative: here, only short contact with ice is not enough to cause symptoms.

If necessary, the doctor may prescribe additional tests and examinations if he suspects that the cold urticaria appeared against the background of another disease.

Provocative tests with cold objects do not always show cold urticaria. About a third of patients are insensitive to them, but other methods of diagnosis have not yet been developed.

How cold allergies are treated

Treatment of cold urticaria is symptomatic. To relieve the condition, antihistamines are usually used, such as cetirizine in a high dosage of up to 40 mg per day. The exact dosage and treatment regimen is determined by the doctor.

Patients with a severe cold allergy who are insensitive to antihistamine therapy may be prescribed the monoclonal antibody drug omalizumab. The drug reduces the number of IgE molecules and thus reduces the number of mast cells that can be activated in an allergic reaction.

Monoclonal antibody preparations have appeared recently. Previously, cold urticaria resistant to antihistamines was usually treated with cyclosporine, systemic glucocorticoids, and other drugs that suppress the immune system.

Both omalizumab and medications that affect the immune system have side effects. They should only be used when prescribed by a doctor. Most patients with a cold allergy do not need such serious treatment.

People with cold urticaria should also avoid contact with the cold, and it is especially important to protect yourself from hypothermia. It is strictly forbidden to swim in cold water, so it is advisable to avoid water sports.