Strange and rare allergies doctors treat

2. Water

People who suffer from aquagenic urticaria, also known as ‘water allergy,’ develop hives and itchiness shortly after their skin is exposed to water.

This condition, considered a rare disease, mostly affects women and can develop during puberty. The underlying cause is unknown, and experts think it could be caused either by allergens dissolved in water (in which case water wouldn’t really be the cause) or by interactions between a person’s skin and water that create a substance that triggers hives.

There is limited data on successful treatments, but for some patients, antihistamines — which are often used to counteract allergic reactions — help. Some other medications, light therapy and sodium bicarbonate have been found to be helpful as well.

3. The sun

Rare sufferers of solar urticaria develop a sore, itchy rash after their skin is exposed to sunlight.

Another rare condition that can make life difficult is solar urticaria, which can develop at any point in a person’s life. Reactions frequently occur after even a short amount of sun exposure, and are more likely to happen on parts of the body that are less frequently exposed to the sun.

While this condition is poorly understood, researchers have found that it can be triggered by UVA or UVB , as well as visible light.

Treatment options include antihistamines, avoidance, and gradual exposure to sunlight to build up a tolerance.

4. Hidden parasites in fish

Certain parasites that are becoming more common can start to trigger allergy symptoms in people who consume them.

An allergic reaction after a fish dinner may make someone think they’re allergic to fish, but sometimes the culprit is an organism hidden inside the food. The Anisakis simplexparasite, found in temperate waters around the globe, can infect a number of kinds of fish or squid, and has also been found in chicken meat.

An Anisakiasis infection alone can be severe, causing abdominal pain, vomiting, diarrhea, and symptoms that mimic Crohn’s disease. But people can also develop immune reactions to these parasites that manifest as asthma or severe allergies (with symptoms like hives or anaphylaxis). It’s even possible to develop these allergies if fish is well cooked or even via regular contact with fish, as has happened with factory workers.

Treatment options are limited but include antihistamines or emergency adrenaline.

5. Cold

Sudden drops in temperature can trigger reactions with potentially life-threatening throat swelling in some rare cases.

Sudden drops in temperature are rarely pleasant, but for certain people they can be deadly. Sufferers of cold urticaria are most frequently young adults. A sudden change in temperature is usually responsible, especially in situations where it affects the whole body, like jumping into water.

The condition is not well understood, but it can go away naturally in a few months or years. Patients are told to be careful before engaging in activities like swimming. Antihistamines can help block certain severe reactions.

6. Exercise

In a small number of people, physical exercise can trigger hives or even life-threatening anaphylaxis.

This condition has been described in medical literature since at least the 1970s. Researchers think the reaction could be triggered by consuming certain foods or medications before exercise. Potential triggers include seafood, celery, wheat, or cheese; medical drugs that may lead to this reaction include NSAIDs and Aspirin.

For treatment, doctors tell patients to avoid exercise after consuming certain substances and to work out with a partner who can administer life support if needed.