Allergies: Common Symptoms and Risks for Health

Your immune system is the source of allergies, targeting actions when the body develops responses to a natural, seemingly harmless substance. In its quest to protect the body from harm, the immune system may misread a substance as a danger, creating antibodies to prevent it from causing harm. As one of the world’s most common chronic health conditions, allergies affect young and old, with symptoms ranging from mild to life-threatening (anaphylaxis). 

Some people have family histories of allergies, increasing the risk to future generations. Others may develop an allergic reaction for no reason. Food allergies can occur anytime to anyone, even after a lifetime of enjoying a particular item. 

The immune system responds to the allergen by over-reacting and attacking it with newly created antibodies that target the offending substance. Once the body develops antigens against a substance, the person becomes allergic to that allergen. Repeated exposures can increase the severity of the allergy attack. 

The immune system protects the body from invading viruses, germs, bacteria, and other microorganisms. It is a complex system that uses white blood cells (lymphocytes) to attack unwanted invaders. Whether ingested, inhaled, or absorbed through the skin, allergens can trigger many different responses, ranging in severity based on the type of the allergen, the amount encountered, and the reaction of the body’s immune system.

Symptoms of Different Allergies

Allergies appear in many ways, and the symptoms can change over time. Fatigue, dark circles under the eyes, sinus or ear infections, postnasal drip, and headache may be signs of undiagnosed allergies. Fever is not a symptom of allergies, so if you have that in conjunction with any of the issues mentioned below, it is likely due to another cause. 

The most common allergy symptoms are:

  • Sneezing, runny, stuffy nose, itching of the nose, eyes, or roof of the mouth

Allergic rhinitis, or hay fever, encompasses allergic reactions and inflammation in the nose, including congestion, stuffy nose, sneezing, runny nose, or itching in the nose, eyes, or roof of the mouth. These symptoms are often due to external allergens, such as pollens, dust/dust mites, pet dander, cockroaches, or mold. 

  • Watery, red, or swollen eyes

Indoor and outdoor allergens can trigger eye issues, including itching, redness, tearing, and irritation. Airborne allergens can get under the eyelid, causing increased and long-lasting problems. Eyedrops may help with these issues. Some food allergies can cause facial swelling that can also impact the eyes. 

  • Swelling of the lips, tongue, face, or throat

Also called angioedema, an allergic reaction often brings about this sudden swelling and can become severe or life-threatening if it impacts the throat and airway passages.

  • Itching or rash all over the body

Skin allergic reactions can occur due to skin contact with the allergen or consumed exposure, such as food or medication. Being mindful of any rash, itching, hives, blistering, redness, or swelling is essential, as that can help narrow the field to determine the cause. Skin reactions typically appear within 48 hours of the initial exposure. 

  • Nausea and vomiting

These symptoms are more likely associated with food allergies as the body tries to rid itself of the invading substance.

  • Cough

Unlike the typical cough associated with a cold, often accompanied by phlegm, a dry, chronic cough is often a sign of allergies or asthma. However, when allergic rhinitis accompanies the cough, you may experience sneezing and a runny or stuffy nose. It may be due to asthma when accompanied by wheezing or chest tightness. 

  • Wheezing or shortness of breath 

Allergies can trigger swelling and narrowing in the throat or airways to the lungs, resulting in wheezing. While also a sign of chronic obstructive pulmonary disease (COPD) and asthma, it is crucial in children to check if this is due to allergies or asthma. 

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  • Anaphylaxis

Anaphylactic shock is the most dangerous reaction to an allergy, causing a potentially life-threatening situation. Many of the symptoms listed above can occur, but their reactions may come on suddenly or in greater severity than in the past. Loss of consciousness is possible, as are confusion, headaches, and sweating. Chest pain and tightness are possible.

One of the most concerning issues is body tissue swelling, which can lead to impaired breathing and death when in the throat. Sudden blood pressure drop can also occur with anaphylactic shock. Carrying an injectable epinephrine pen is crucial for people with allergies as that can stimulate the adrenal glands to improve breathing and increase heartbeat force and rate.

What Can Cause Allergic Reactions?

Allergic reactions can be seasonal, such as when specific trees, grasses, or pollens are in bloom. Some types of mold that appear during rainy seasons that cause leaves to become and stay wet may also cause allergies. Common indoor allergens include dust mites, animal dander, mold, cockroaches, and chemicals (such as those used in cleaning products) and are often year-round. 

Allergic reactions may increase in response to outside factors, such as:

  • A wind that transports allergens or lack of which that can ground allergens around you
  • Rain
  • Humidity
  • Warm days and cool nights
  • Early morning hours

When allergic reactions occur, the body produces a specific immunoglobulin E (IgE) antibody that attacks only that allergen. The IgE antibodies seek out the offending allergen, transport them to mast (allergy) cells, and attach them to receptors that cause the allergy cell to release chemicals such as leukotrienes and histamine, which causes the allergy symptoms. 

Allergies are not contagious, and you cannot transmit them to another person while having an attack. However, some allergies are increasingly common among family members, such as food allergies like shellfish and nuts. If a closely related family member has an allergy, you may have an increased risk of developing the same. 

Along with genetics, lifestyle factors such as exposure to secondhand smoke and pregnant women who smoke can increase allergy risks in children. 

Common allergens include:

  • Tree and grass pollen (hay fever): While many types of tree, plant, and grass pollens can affect people, the lists below highly some of the most common and highly allergic ones. Many others can also cause allergies, some specific to various geographical regions. 
  • Some of the most common and highly allergic tree pollens are:
    • Willow
    • Pecan
    • Mulberry
    • Walnut
    • Oak
    • Hickory
    • Box elder (maple)
    • Ash 
    • Alder
    • Birch 
  • Some of the most common and highly allergic grass pollens are:
    • Bermuda
    • Orchard
    • Fescue
    • Timothy
    • Sweet vernal
    • Rye 
  • Some of the most common and highly allergic plant and weed pollens are:
    • Ragweed
    • Sagebrush
    • Russian thistle 
    • Cocklebur 
    • Jasmine vine
    • Wisteria
    • Juniper
    • Cypress 
    • Chamomile
    • Daises
    • Sunflowers
    • Chrysanthemums
    • Amaranth 
  • House dust mites and mold: Dust and dust mites are highly problematic for some people. Vacuuming and dusting can cause these particles to become airborne, increasing symptoms that can lead to rhinitis, asthma, and eczema. Cockroaches, pet hair, fur, feathers, pollen, mold, and dust mites can trigger dust allergies. Switching from carpet to hard flooring, removing drapes and curtains, covering pillows and mattresses with mite-proof covers, decreasing indoor humidity, and frequently washing bed linens can help. 

Mold can grow anywhere, but especially in moist areas. Tiny mold spores can travel far when they become airborne. With about 1,000 species of mold in the US, this allergy can cause many problems, especially once it is in the home. Finding the source of the mold and eradicating it is crucial. 

Cockroaches are placed in this group as they cause in-home allergies. These insects carry proteins in their spit, feces, eggs, and dead body parts, which can cause allergic reactions. 

  • Foods, such as peanuts, milk, and eggs (food allergy): While any food can cause an allergic reaction, approximately 90% of food allergies are due to 8 types of food: eggs, shellfish, fish, milk, peanuts, tree nuts, soy, and wheat. Roughly 50 million people in the US suffer from at least one type of food allergy. Food allergies run in families and can be life-threatening, with symptoms often occurring quickly.
  • Animal fur, particularly from pets like cats and dogs: While nasal sprays, bronchodilators, and antihistamines can help with symptoms of pet allergies, avoiding exposure is the better option for most people. Immunotherapy in the form of allergy shots may help. Some hypoallergic dog breeds may be suitable for people with animal dander allergies. 

Along with pet fur and dander, saliva, and urine can also cause allergic reactions in some people.

  • Insect stings, such as bee and wasp stings: Some insects excrete toxic venom that can cause a potentially life-threatening allergic reaction (anaphylaxis), including fire ants, wasps, bees, yellow jackets, and hornets. Some people are also highly allergic to mosquito bites and experience significant swelling, warm skin, and redness around the affected site. Bed bugs can also cause allergic reactions in some people.
  • Certain medicines: Most medications come with warnings about allergic reactions because any component/ingredient in the medicine could create a problem for some people. Whether topical, injected, or oral, it is essential to know if you have allergies and to let any doctor know before receiving treatment. Insulin, antibiotics, biologics, chemotherapy drugs, and nonsteroidal anti-inflammatory drugs (NSAIDs) are among the medications most likely to cause allergies.
  • Latex allergies: Latex is a natural rubber typically found in balloons, rubber gloves, bandages, rubber balls, and condoms. Contact dermatitis, a skin irritation that occurs at the site of skin exposure, often develops quickly. Non-latex gloves are available for people requiring medical treatment or for food preparation, hair coloring, and other needs. 
  • Contact allergies: From natural substances to chemicals, the following items can trigger an allergic reaction upon contact:
  • Oak
  • Poison ivy
  • Sumac
  • Fragrances
  • Nickel
  • Formaldehyde
  • Hair dye
  • Personal care products
  • Makeup
  • Antibacterial ointments
  • Leather tanning chemicals 


Because allergic reactions can range from mild to severe and life-threatening, treatment options may differ significantly. Carrying an epinephrine pen can immediately reverse anaphylactic symptoms while awaiting medical help. Corticosteroids help reduce swelling in cases of severe allergic attacks. Antihistamines can help reduce congestion and itching. 

You can monitor your allergies to see when they are the worst. Tracking pollen and mold counts, weather reports, and seasonal news information can help you keep allergies at bay. Keeping doors and windows shut during allergy season, showering, washing your hair, washing your clothes when you get home or after being outdoors, and wearing a mask outside can help reduce exposure to plant and environmental allergens. 

For foodborne allergies, avoiding places serving these items can help reduce exposure, such as not going to seafood restaurants with a shellfish allergy. Sterilizing wipes or seat and table covers before sitting in a chair, at a table, or on public transportation can help reduce the risk of contact contamination. 

Taking care to avoid exposure to allergens is the first step. Preparing yourself for any possible reactions comes next, including keeping necessary medications close at hand. Seek help from a qualified medical specialist when allergy symptoms are a concern.