Cold urticaria: symptoms, triggers, safety and treatment

Urticaria, also known as hives, causes itchy raised skin reactions called weals. The British Association of Dermatologists (BAD) says weals may be set off by a physical trigger such as cold, pressure or friction, and calls this type "inducible" urticaria because hives are induced by a specific stimulus rather than appearing spontaneously. Cold urticaria is one of these.

PCDS describes cold urticaria as rare, tending to affect young and middle-aged adults. The NHS also lists cold, such as cold water or wind, among the triggers that can cause hives.

BAD says the main symptom of urticaria is itch, and that weals may be round or ring-shaped, may join together and typically disappear of their own accord within 24 hours. Deeper swelling, called angio-oedema, often occurs in urticaria and usually affects soft areas of skin such as the eyelids, lips or inside the mouth.

In cold urticaria specifically, PCDS says symptoms develop at sites exposed to cold, for example in a cold wind, or as fullness of the throat or swelling of the lips after drinking cold liquids.

BAD notes that urticaria generally has no direct effect on general health but can have a high impact on quality of life, including mood, work and relationships.

PCDS warns that because of massive histamine release, people can develop life-threatening hypotension (low blood pressure), swelling of the throat and mouth, and anaphylaxis if they are exposed to sudden temperature drops, such as plunging into a cold swimming pool or a large body of water. It advises that patients with cold urticaria should learn to protect themselves from a rapid drop in body temperature.

Its guidance says aquatic activities such as swimming and surfing should be done under supervision at all times, and that patients should carry adrenaline pens (Epipens) and know how to use them.

The NHS says to call 999 if your lips, mouth, throat or tongue suddenly swell, you are breathing very fast or struggling to breathe, your throat feels tight or you are struggling to swallow, your skin, tongue or lips turn blue, grey or pale, or you suddenly become very confused, drowsy or dizzy. These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

The mechanism is histamine release from mast cells in the skin, as in other types of urticaria. BAD explains that urticaria is caused by the release of histamine and other chemicals from mast cells, and that it is often thought of as an allergy but usually results from histamine release for other reasons.

PCDS says up to 96% of cold urticaria cases are idiopathic, meaning no cause is found. A few are secondary to underlying disorders such as cryoglobulinaemia, haematological conditions or infection, which is one reason specialist assessment is advised.

BAD says that for urticaria in general, the appearance or a description of it is usually enough for a diagnosis, and there is no special test that reliably identifies the cause of spontaneous urticaria. For cold urticaria, PCDS shows that the diagnosis can be confirmed by inducing an urticarial wheal with an ice cube placed on the forearm for 5 minutes.

Because a small number of cases are linked to other illnesses, a dermatologist may arrange further tests. PCDS says patients with cold urticaria should be referred to a dermatologist for further assessment and advice on management.

PCDS sets out a stepwise approach for physical urticarias. Step 1 is general measures: avoiding or reducing triggers. Step 2 is a second-generation H1 antihistamine, which it describes as the mainstay of treatment. Step 3 is referral, and it states that all patients with cold urticaria (and solar urticaria) require referral.

BAD explains that antihistamine tablets block the effect of histamine by reducing itch and the rash in most people but may not relieve urticaria completely. If urticaria occurs frequently, antihistamines should be taken regularly every day, and it has become common practice to increase the daily dose of non-sedating H1 antihistamines up to fourfold if needed to control symptoms. You and your doctor may need to try different ones to find one that suits you.

PCDS lists omalizumab as second-line treatment and ciclosporin as a third-line treatment for cold urticaria, both of which are specialist decisions. PCDS also says patients should be reassured that it is safe to take antihistamines for as long as needed, as physical urticarias may last for months or many years.

Call 999 for any sign of a serious reaction, such as swelling of the lips, mouth, throat or tongue, a tight throat, difficulty swallowing or breathing, or collapse.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if hives do not improve after 2 days, the rash is spreading, hives keep coming back, you also have a high temperature and feel unwell, or you have swelling under the skin that might be angioedema.

If you suspect a medicine is involved, tell your doctor. BAD says almost any medicine can cause urticaria, but painkillers such as aspirin, ibuprofen and codeine are among the most likely. Ask a pharmacist or doctor before taking them if you have hives.

The practical points drawn from PCDS and BAD are to protect yourself from sudden cold exposure, avoid unsupervised swimming and cold-water activities, and discuss with your clinician whether you should carry an adrenaline pen.

BAD says some people with urticaria have other conditions such as thyroid disease or other autoimmune disorders, which a GP can consider. If urticaria is affecting your mood, work or relationships, tell your clinician, as BAD notes this impact is common.

On the NHS, a GP can start antihistamine treatment and refer you to a dermatologist or allergy service, which PCDS says is needed for cold urticaria. Specialist decisions about adrenaline pens and treatments such as omalizumab are made by those services. Some people choose to see a private dermatologist or allergist, and the same safety advice applies regardless of where you are seen.