Surprising Allergies: Types, Reactions, and Treatments - Health.com

When you think of allergies, what comes to mind? Pollen, mold, or animal dander? Or peanuts? These substances are well-known allergens. (That means they can trigger an immune response in the body). A number of surprising or weird allergens, including red meat or coffee, can also provoke an allergic reaction.^1,2

In rare cases, some people's skin might be very sensitive to other factors, such as cold weather or their own sweat.^3,4 While these aren't true allergies (they're called hypersensitivities), certain people can develop a skin rash when exposed to these elements.

Learn more about these uncommon allergies and hypersensitivities and how to avoid and treat them.

In the U.S., about 4% of adults and 5% of children have food allergies.⁵

When you have a food allergy, eating or being exposed to certain foods can set off an allergic reaction. Your body misreads the food, or a substance in the food, as a dangerous invader. In response, your immune system mounts a defense. It sends specialized white blood cells, antibodies, and other immune cells to fight the allergen.⁶

Food allergies may affect your skin, breathing, and gastrointestinal tract (stomach and intestines). Common symptoms include hives (a sudden itchy rash) and swelling of the skin, lips, tongue, or eyelids. You may also experience nausea, vomiting, diarrhea, abdominal pain, sneezing, or a runny or itchy nose. Severe allergic reactions can cause anaphylaxis—a life-threatening reaction that can reduce blood pressure and disrupt breathing.⁷

How to avoid: The best way to prevent a food allergy is to avoid consuming the food. That's especially necessary if you have a history of severe allergic reaction.⁷

Here are some food allergies which may be less well known.

Coffee

An allergy to coffee is very rare. The main allergens are likely certain proteins within the coffee bean. For instance, in a 2012 study, researchers identified a specific protein in the dust of raw coffee beans (green, pre-roasted) that led to allergic reactions among some coffee farmers. This protein is likely stable to heat and may be present in the coffee that you drink. But more research is needed to understand coffee allergens.¹

People might mistake a caffeine intolerance for a coffee allergy. Like other food intolerances, caffeine intolerances are more common and don't involve an immune response. Instead, people will usually experience abdominal pain and other gastrointestinal symptoms when consuming high amounts of caffeine from different sources, whether from coffee, teas, or sodas.⁷

A true coffee allergy triggers an almost immediate reaction. It can lead to itchy eyes, a stuffy nose, or pink eye.¹

Red meat

A red meat allergy is also known as tick bite meat allergy or alpha-gal syndrome. Alpha-gal is a type of sugar found in most mammals, although not in humans. People with this allergy can have potentially life-threatening reactions after consuming red animal meat, including pork, beef, lamb, and venison. Cow milk and gelatin (a common coating for some oral medications) may also trigger a reaction.²

This allergy can develop at any point of a person's life, usually after a tick bite. In the U.S., the lone star tick might be primarily responsible, as most allergy cases are reported in the South, East, and Central regions—the tick's natural habitat.^8,9 However, more research is needed to understand why a tick bite can trigger red meat allergy.²

Typically, symptoms of an allergic reaction appear two to six hours after consuming alpha-gal. Cases can be mild to severe. If you have this allergy, you may not necessarily have a reaction each time you consume products with alpha-gal. But in severe cases, it can cause anaphylaxis.²

If you have this allergy, consider eating other protein sources that don't contain alpha-gal, including poultry and fish.²

Wine

Research suggests that drinking red wine in moderation—up to one glass (5 ounces) a day—may have several health benefits, such as lowering the risk of heart disease and reducing stress and anxiety.¹⁰ However, some people can be allergic to red wine and other types of wine.

Itchy eyes, a stuffy or runny nose, and a red, itchy rash are common wine allergy symptoms. People with an allergic condition, such as asthma or hay fever, may be more likely to experience an allergy to wine.¹¹

It is unclear what triggers an allergic reaction to wine. Some people may be allergic to the proteins in grapes. Others may react to yeast or other ingredients used for processing and cleaning wine. Proteins from insects that can contaminate crushed grapes may trigger a reaction as well.¹¹

Other times, people might mistake a wine intolerance for a wine allergy. Unlike a true allergy, an intolerance to a substance doesn't involve an immune response.¹¹ A person with alcohol intolerance may develop a red flush to the face about 30 minutes after consuming wine or other alcoholic drinks. This is common in some Asian people who genetically may have less of the protein that breaks down alcohol in the body (aldehyde dehydrogenase). If you are allergic to other ingredients in wine but can tolerate alcohol, you may be able to drink beer or liquor.¹²

Several sensitive skin conditions can cause overactive immune responses when a person is exposed to certain environmental factors, like temperature changes. The following hypersensitivities aren't technically allergies because allergens are defined as physical, foreign substances.⁶ But some people might refer to them as allergies.

Water

Water is essential for your health: About 60% of your body is made up of water, which helps flush out toxins and regulates body temperature.¹³ But it may be surprising to learn that people can break out in hives and rashes after touching water. This water allergy is known as aquagenic urticaria.¹⁴

Why it happens: Scientists don't know what causes aquagenic urticaria. Some reported cases show a potential family history for the allergy. But experts have yet to identify specific genes linked to this condition.¹⁴ Any type of water can trigger this allergy, including distilled (purified) water, rainwater, saltwater, tap water, sweat, and tears.^14,15 Based on reported cases, reactions happen only when there is direct skin contact.¹⁴

Only about 50 cases of aquagenic urticaria have been reported in the medical literature, though experts believe this is an undercount. Skin reactions usually begin within 30 minutes of contact with water and can last up to two hours.¹⁵ It most often affects the upper arms, chest, and back. In rare cases, wheezing and shortness of breath may also occur.¹⁴

How to avoid: Because water is essential for your body, it is unrealistic to avoid it completely. Instead, healthcare providers can prescribe antihistamines, topical creams, and other treatments to soothe skin irritation and itching. If you have a water allergy, try reducing your time being exposed to water, such as when you're showering or swimming.¹⁴

Sunlight

Sunlight and other sources of ultraviolet (UV) light can cause a hypersensitive immune response that worsens several skin conditions. These photosensitive conditions are known as photodermatoses. Symptoms will vary by the type of condition but typically include redness, itchiness, blisters, and in some cases, hives on the skin.¹⁶

Some examples of photodermatoses include:

• Polymorphic light eruption (PMLE): This is the most common type of photodermatosis. It has been linked to several gene mutations.¹⁷ PMLE occurs in approximately 10–20% of populations from the U.S., Central Europe, and Scandinavia.¹⁶
• Solar urticaria: A person with this condition develops a recurring skin rash after a few minutes of sunlight exposure. Typically it starts in early adulthood, though it is not clear why some people can develop it.¹⁸
• Photoallergic dermatitis: This is a very rare eczema-like rash that produces redness and scaling. Light-sensitive chemicals found in sunscreen can react with sunlight and trigger symptoms.¹⁶

How to avoid: Protect your skin from the sun by wearing sunscreen and long-sleeved clothing that adequately covers any exposed skin. If you have photoallergic dermatitis, avoid using chemical sunscreens that you may be sensitive to.¹⁶

Sweat

You can sweat from a hot day, when exercising, or even when you're stressed. While a sweat allergy may seem unlikely, it's not unheard of. Some people develop pin-sized, raised bumps (weals) when sweating—this condition is called cholinergic urticaria. If you have atopic dermatitis (AD), a type of eczema or chronic inflammatory skin disease, you may have worsening itchy rashes when sweating.⁴

Why it happens: The cause of sweat allergy isn't entirely clear. But sweating helps your body release water, sodium, and toxins like dust. This also changes the pH of your skin, making it less acidic. These factors can trigger an allergic reaction in some people, particularly if they have existing skin damage or rashes from AD. People with AD or cholinergic urticaria may also be overly sensitive to their own sweat.⁴

Another factor could be differences in skin microbiome: the bacteria, fungi, and other microorganisms that naturally live on your skin. In people with either sweat allergy, scientists have identified a possible sweat allergen—a protein that is produced by a common skin yeast (Malassezia globosa) when the body is sweating. However, there are likely other sweat allergens that scientists have yet to discover.⁴

How to avoid: It is unrealistic to avoid sweating entirely. But reducing the time that sweat remains on your skin can help, particularly if you have an AD-related sweat allergy. Try showering shortly after exercising. For any sweat sensitivity, speak to your healthcare provider about treatments and ways to manage symptoms.⁴

Cold temperatures

Although very rare, it is possible to be allergic to the cold. Known as cold urticaria, common symptoms include hives, which can appear as red, itchy welts (bumps) or swelling on the skin. Hives can also develop on areas of soft tissue, like the tongue or throat.³

Symptoms usually begin within one to five minutes after exposure to the cold and may go away within one hour or longer. In severe cases, it can be potentially life-threatening when anaphylaxis happens.³

About 5 out of 10,000 people can have this allergy. People of any age can develop it, but it usually starts between ages 10–40.³

Why it happens: The exact cause is unknown, but some people may be genetically predisposed to it. They may have certain gene mutations that lead the immune system to overreact to colder temperatures, resulting in inflammation in the skin.¹⁹ Common allergy triggers include cold showers or swims, winter weather, air conditioning, cold winds, and consuming cold foods and beverages.³

How to avoid: In general, try to limit your exposure to the cold if you have this allergy. During winter months, avoid outdoor exposure to the cold by staying indoors (whenever possible) and wear enough layers of clothing to warm your skin. Be cautious of entering indoor places with colder temperatures, and avoid consuming ice cold drinks and desserts.³

If you suspect you have an allergy or hypersensitivity, visit a healthcare provider for proper diagnosis and treatment.⁶

If you experience mild allergic symptoms, like a stuffy or runny nose, itchy throat, or headaches you can usually manage it with over-the-counter medications, like antihistamines used for seasonal allergies.⁷ But mild reactions can worsen unexpectedly, and it's important to see a doctor.⁶ For more serious reactions, your healthcare provider may prescribe steroid medications to help reduce inflammation.⁷

However, if you experience severe, life-threatening symptoms, seek immediate medical attention. Signs of anaphylaxis usually affect more than one part of the body and can include difficulty breathing, wheezing, a swollen throat, hives all over your body, lightheadedness, vomiting, and diarrhea.²⁰

In an emergency, a healthcare provider will administer a shot of epinephrine (also known as adrenaline). This drug helps counteract the effects of a severe allergic reaction by boosting blood pressure and relaxing muscles along the airway.²¹ If you are at known risk of a serious allergy, your provider may prescribe a supply of epinephrine autoinjectors to have on hand in case of an emergency. Talk with your provider about how to use it and be sure people in close contact with you are prepared to use it as well.²⁰

Depending on the type of allergy you have and how severe it is, your healthcare provider may also suggest immunotherapy. This is a type of treatment often used for food allergies, where you would consume a small amount of the food allergen. The goal is to build your tolerance to the food and reduce your immune system's sensitivity to it.⁷

Also, consider getting an allergy test, such as a skin prick test, so you'll know exactly what your triggers are. A skin prick test checks how your skin (usually your forearm) reacts to an allergen, such as pollen and certain foods. Other allergy tests involve blood work to check for antibodies when a blood sample is mixed with an allergen.⁷

An allergic reaction is triggered when a harmless allergen enters the body. Your immune system misreads the allergen as a toxic invader and attacks it. Although uncommon and sometimes rare, people can have an allergic reaction to everyday foods, like coffee or red meat. And though they aren't true allergens, cold temperatures, sweat, and other hypersensitivities can trigger skin reactions in people with rare conditions.

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