For most people, cold weather is an inconvenience that requires an extra layer of clothing or turning up the thermostat. For others, exposure to cold can trigger an allergic reaction severe enough to cause them to collapse.
Cold allergy is a rare condition but potentially dangerous in that contact with cold temperatures causes our immune system fails. The results can be allergies, swelling, pain and, in some cases, anaphylaxis potentially fatal.
The condition was first described in 1792 by the German physician Johann Peter Frank. We now know that it is almost twice as common in women than in men, with the average age of onset in the early 20s, although it can affect people of any age.
But there is good news: 24% to 50% of peoples with this condition register improvements, or even full recoveryover the years.
This condition assumes two waysexplains Adam Taylorprofessor of Anatomy at Lancaster University, in an article in .
A primary cold allergy It is the most common, representing around 95% of cases and often has no known cause. The remaining 5% are classified as secondary allergywhich is associated with underlying conditions or infections, such as Epstein-Barr viruscertain types of lymphoma (blood cancer), HIV and hepatitis C.
Primary cold allergy typically causes rash, swellingpapules, or allergy, although some people also report fatigue, fever and pain joints.
Symptoms usually appear when the skin is exposed to coldbut can also occur when the skin heats up again. Triggers are not limited to cold weather: may include swimming, eating frozen foodsdrink cold liquids and handle cold objects.
With the exception of some very rare genetic causes, remains unknown the reason some people develop primary cold allergies. What is clear is that the mast cells are involved. These white blood cells resident in connective tissues work by alerting the immune system to signs of danger or microbes.
What triggers its activation in cold allergy remains a mysteryalthough one theory suggests that exposure to cold causes the body to produce so-called autoallergenic – substances that trigger an immune response against the body’s own tissues. More research is needed to understand how this happens.
When mast cells are activated, lrelease a chemical substance call histaminewhich works as an alarm that alerts other immune cells to move quickly to the area. It also causes the blood vessels in that part of the body to tighten. dilate and become more “permeable”which causes the characteristic swelling, redness and itching.
Usually this answer is helpful – additional blood flow and leaky blood vessels allow immune cells to leave the bloodstream and enter surrounding tissue to combat a genuine threat.
But in cold allergy, it is a false alarm. The body is mounting a large-scale immune response when there is nothing to fight, causing discomfort without any benefit.
The doctors test cold allergy by placing an ice cube on a patient’s forearm and watching what happens after they remove it. The test must be done by a healthcare professional because, in around 20% of cases, it can trigger anaphylaxis.
The condition is quite rareaffecting 6 in every 10,000 people, but may be subdiagnosticadasince not all patients have severe symptoms and, in some countries, particularly tropical ones, temperatures tend not to drop below 0°C in winter.
Once diagnosed, It’s important to help people people with cold allergies should avoid or recognize their trigger temperatures. There are two measurements that can be evaluated, depending on the availability of measuring devices.
One is the cold stimulation time testwhich indicates how quickly the skin reacts to the cold with a lump or rash; a shorter time suggests a more active response. The other measure is the critical temperature thresholdwhich is the hottest temperature that can still trigger symptoms.
Antihistamines and beyond
There are treatments that can help control symptoms. One approach is to take antihistamines before exposure to cold environments or stimuli.
For many people, however, a standard dose of oral antihistamine is not enough. Sometimes, a dose up to four times higher may be required to standard. The downside is that some antihistamines can have a sedative effect, so caution is necessary. About 60% of people with cold allergy respond well to treatment with antihistamines.
During short attacks, other medications, such as corticosteroidscan be beneficial, although long-term use brings side effects, such as weight gain, indigestion and mood changes.
Severe cases can be treated with a monoclonal antibody called Omalizumab, which targets immunoglobulin Ea molecule involved in the activation of mast cells.
Another option is desensitization: gradually expose the skin to cooler temperatures over several days (although sometimes over a few hours) to try to overcome the response and histamine release. There have been some successes with this approach, but most studies have been small.
For people with the most severe cases, adrenaline is a life-saving option in response to anaphylaxis, although it appears to be underprescribed in patients with cold allergies.
People with this condition also face a increased risk during surgical procedures, where anesthetic medications reduce core body temperature and operating rooms are kept deliberately cool.
Although they are used warming measures during surgeryfor people with increased sensitivity to cold, this may pose an additional risk.
As winter continues, it’s worth remembering that for some people, the cold is not just uncomfortable – can be genuinely dangerous. Understanding and recognizing cold allergies can make all the difference.
