Cold Allergy: What It Is, Why It Happens, and How It Manifests

Frost, wind, a wet glove — and the skin turns red, itches, and breaks out in hives. A reaction to cold really does exist and looks like cold urticaria. We explain how to recognize it, what a doctor tests for, and in which cases you must not postpone a visit to the doctor.

Does a cold allergy exist and what is it

It does. Cold allergy, also known as cold urticaria, is a reaction in the form of urticaria-like eruptions or red patches in response to cooling of the body or a part of it. The eruptions are accompanied by itching, and swelling of the limb often joins in. The condition can be hereditary and acquired. Doctors distinguish four types of cold urticaria: primary, secondary, reflex, and familial.

Why the skin reacts to frost: possible causes

On contact with cold, skin mast cells release histamine: blood vessels dilate, and redness, itching, and hives appear. The mechanisms that trigger such an abnormal release of histamine are in most cases unclear. Strictly speaking, cold urticaria is not always a true allergy: its development is not mediated by immunoglobulin E and is associated with degranulation of mast cells under the action of a physical factor — cold. Familial cold urticaria is distinguished separately: it is a form of cryopyrin-associated periodic syndrome, inherited in an autosomal dominant manner and associated with a mutation in the NLRP3 gene. Besides cold, a similar rash can be provoked by sun, sweat, emotional stress, infections, physical exertion, and water; the cause of urticaria often cannot be established.

How cold allergy manifests on the hands, face, and legs

On cooled areas, patches or hives with polycyclic-shaped edges appear, which blanch on pressure. At the same time, itching and burning, local redness, and swelling appear. The rash lasts from several minutes to several days, and an ordinary hive rarely persists longer than 48 hours. With a large area of eruptions, a drop in blood pressure and collapse are possible, and with severe reactions — swelling of internal organs; the development of asthma has also been described. Typical sensations with such a rash:

• itching and burning on cooled skin;
• hives and patches that blanch on pressure;
• swelling of the limb;
• local redness and swelling.

With the end of the warm seasons, constant weakness throughout the body and nervousness may appear, unrelated to swelling.

How a reaction to cold is diagnosed

The diagnosis is made by an allergist, and the main reference point is the cold test: a piece of ice is placed on the skin of the limb for 2–3 minutes. With a positive result, a couple of minutes after the ice is removed, a typical cold reaction occurs at the site of cooling. The doctor then differentiates the conditions: mast cell membrane instability (the very variant not associated with immunoglobulin E) and familial cold urticaria as a form of cryopyrin-associated syndrome. Ordinary urticaria is often recognized already on skin examination; in some cases a skin biopsy or blood tests are done, and specific allergy testing in urticaria is in most cases uninformative.

When to see a doctor about a reaction to cold

Urticaria itself is usually harmless and resolves within a few days. A reason to make an appointment with a doctor is a rash that does not improve within 2 days, spreads over the body, returns again and again, is accompanied by a high temperature and malaise, as well as swelling under the skin (angioedema). If urticaria persists longer than 6 weeks, it is called chronic; in most people it resolves on its own in less than a year.

Cold rash by itself is not a reason to call an ambulance. Call 103 or 112 if the lips, mouth, throat, or tongue suddenly swell, breathing becomes rapid and difficult, a feeling of tightness in the throat appears or swallowing is difficult, the skin, tongue, or lips turn blue, gray, or pale, or the person faints.

This material is for reference: it helps to understand what happens to the skin in frost, but does not replace a doctor's consultation — only a specialist at an appointment will determine the cause of your rash.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer