Symptoms of Allergies

Allergy symptoms vary widely, but all are the product of an abnormal immune system reaction to a normally harmless substance (an allergen). When a person who is allergic encounters the trigger, the body reacts by releasing chemicals that affect the skin, respiratory system, digestive tract, and more to produce allergy symptoms. These can range from a runny nose to an itchy rash or even to a life-threatening asthma attack or anaphylactic reaction.

Young girl sneezing because of allergy
Sollina Images Collection / Photodisc / Getty Images 

Frequent Symptoms

In children, allergic disease first occurs as atopic dermatitis (eczema) or food allergies. Children with atopic dermatitis are then at an increased risk of developing allergic rhinitis and asthma; both are more likely to occur in school-age children.

Typically, atopic dermatitis goes away by adulthood, as do many types of food allergies. Allergic rhinitis and asthma, however, most often start during the adolescent, teenage, and young adult years, and are likely to persist throughout a person’s life. The severity of allergic symptoms, however, may wax and wane, and even temporarily disappear.

There can be some overlap of allergy symptoms between types of allergies, so it's best to consider what is most frequently associated with which conditions.

Atopic Dermatitis

Atopic dermatitis, or eczema, is typically the first sign of allergies and is seen in 10% to 20% of all children, frequently during infancy. It is characterized by itching, with rash formation at the sites of scratching. The rash is typically red and dry, may have small blisters, and can flake and ooze over time.

In infants and very young children, this rash involves the face (especially the cheeks), chest and trunk, back of the scalp, and may involve the arms and legs. This distribution reflects where the child is able to scratch, and therefore usually spares the diaper area.

The location of the rash changes in older children and adults to classically involve the skin in front of the elbows and behind the knees. Food and environmental allergies have been shown to worsen atopic dermatitis.

Food Allergy

Food allergies can occur at any age. Almost all people with food allergies will have a skin symptom as a result of eating the culprit food. These symptoms typically occur within a few minutes of eating the food in question, although they can be delayed up to several hours. Skin symptoms may include:

  • Hives
  • Swelling
  • Itching
  • Redness of the skin

Other symptoms of food allergies can include:

  • Nausea
  • Vomiting
  • Stomach aches
  • Diarrhea
  • Breathing difficulties (asthma symptoms)
  • Runny nose
  • Sneezing
  • Lightheadedness

In some cases, children can experience a severe allergic reaction called anaphylaxis, which can be life-threatening.

Nasal Allergies

Allergic rhinitis, including hay fever and seasonal allergies, occurs in up to 30% of adults and up to 40% of children. Symptoms of allergic rhinitis include:

  • Sneezing
  • Runny nose
  • Itchy nose and eyes
  • Nasal congestion

Some people may also experience post-nasal drip, allergic shiners (dark circles under the eyes), and a line across the nasal bridge from an upward rubbing of the palm of the hand on the nose, a sign called the “allergic salute.”

The tissues of the sinuses can also be swollen in an allergic reaction, which can result in pressure inside the head and produce a sinus headache. Fatigue from disrupted sleep is another potential symptom of nasal allergies.

Contact Dermatitis

Some skin allergy symptoms are triggered when your skin comes in contact with an irritant or allergen. Common triggers include nickel, latex, fragrances, poison ivy, hair products, and skin medications. You may experience these skin symptoms:

  • Rash
  • Blisters
  • Burning
  • Itching

You won't usually have the reaction the first time you come into contact with the allergen. But on a future exposure, you will have symptoms.

Rare Symptoms

Anaphylaxis is a life-threatening allergic reaction that can be triggered by exposure to many different substances (allergens). The most common allergies that can produce anaphylaxis are to drugs, insect stings, foods, and latex.

The most common symptoms of anaphylaxis are:

  • Swelling of the face, tongue, lips, throat, or limbs
  • Hives
  • Breathing problems including coughing, wheezing, and difficulty taking a breath
  • Low blood pressure, which may lead to confusion or dizziness

Other symptoms include an irregular heartbeat, chest pain, nausea, vomiting, cramping, body aches, and headaches.

Anaphylaxis is a medical emergency. If you are symptoms of anaphylaxis, call 911 and use an epinephrine injector if you have one. This condition can progress rapidly and be fatal.

Complications/Sub-Group Indications

Allergies can contribute to developing or worsening other conditions.


Allergies are a major cause of asthma, a condition that occurs in about 8% of all people. Though it can occur at any age, it is most often seen in males in the pre-teen years and in females in the teenage years. In fact, asthma is the most common chronic disease in children and young adults. Sometimes asthma is difficult to diagnose in very young children and may require a healthcare provider who is an asthma specialist.

Symptoms of asthma may include:

  • Coughing: This can be the only symptom in some people who have what's called cough-variant asthma. The cough is often dry, hacking, and may be worse with allergic triggers and after exercise. The cough may only be present at night. Cold air may also trigger this symptom.
  • Wheezing: This is a high-pitched, musical instrument-like sound that can occur with breathing in and out in people with asthma. Wheezing usually occurs along with other asthma symptoms and may get worse with exercise and allergic triggers.
  • Shortness of breath: Most people with asthma feel as if they’re not getting enough air at times, particularly when they are physically exerting themselves or when an allergic trigger is present. People with more severe asthma have shortness of breath at rest or wake-up with this symptom during the night.
  • Chest tightness: Some people describe this as a sensation that someone is squeezing or hugging them. Children may say that their chest hurts or feels “funny.”

Nasal Allergy Complications

Nasal allergies can put you at more risk of developing respiratory infections, including lung infections, sinus infections, sinusitis, and middle ear infections (otitis media and otitis media with effusion). Hearing impairment can result.

You may also develop nasal polyps, which are growths in the sinuses or nasal lining. Migraine headaches are also associated with allergies.

When nasal allergies impair sleep, you can have daytime fatigue and poor mental functioning. The medications prescribed can likewise have effects on performance.

Co-Existing Conditions

Over-the-counter medications used to treat allergy symptoms can be unsafe to take if you are being treated for a variety of health conditions including heart disease, diabetes, high blood pressure, thyroid disease, and more.

If you are under treatment for any condition, talk to your practitioner before you begin taking an allergy remedy. It may interact with prescription medications or worsen your condition.

When to See a Healthcare Provider

If you are unable to control your allergies with the occasional use of over-the-counter medications, see your healthcare provider. You should also see your practitioner if your symptoms are impairing your quality of life, reducing productivity at work or school, or disturbing your sleep.

Allergy symptoms in children and older people should always be checked by a practitioner so appropriate medications can be used, including those available without a prescription, and dangerous interactions avoided.

A Word From Verywell

Allergy symptoms can range from annoying to life-threatening, and ongoing symptoms don't have to simply be tolerated. See your healthcare provider or an allergy specialist so you can learn how to avoid allergy triggers and which medications will most improve your quality of life.

Frequently Asked Questions

  • What are the signs and symptoms of a food allergy?

    The symptoms can vary, with some people experiencing more severe reactions than others. Common symptoms include:

    • Tingling or itching in the mouth
    • Nasal congestion
    • Hives or angioedema (tissue swelling)
    • Itchiness
    • Stomach pain
    • Nausea or vomiting
    • Diarrhea
    • Trouble breathing
    • Dizziness or lightheadedness
  • What are the symptoms of wheat allergy?

    The symptoms are more or less the same as any food allergy. However, wheat allergy is often mistaken for gluten intolerance, and vice versa. Conditions like celiac disease (CD) or non-celiac gluten sensitivity (NCGS) are not allergies but can cause many of the same symptoms. Because the treatment of these conditions differs, an evaluation from a gastroenterologist may be needed.

  • What are the symptoms of seasonal allergy?

    Common symptoms of seasonal allergies (including hay fever) include:

    • Sneezing
    • Stuffy or runny nose
    • Red, watery, and itchy eyes
    • Cough
    • Itchy nose or throat
    • Swollen, dark circles under the eyes
    • Fatigue
  • Are pollen allergy symptom worse in the morning?

    They can be, depending in large part on the time of year and the weather. Pollen counts tend to be highest on hot days when it's windy and the air is dry. When it's rainy or humid out, pollen moves less freely.Also, some people may wake up with allergy symptoms in the morning having been exposed to pollen—as well as other allergens such as mold or dust mites—that have circulated through heating or air conditioning systems during the night. while you sleep.

  • What are the symptoms of allergic contact dermatitis?

    Signs and symptoms of allergic contact dermatitis can vary but may involve:

    • Rash or hives
    • Areas of inflamed, red skin
    • Itchiness, often intense
    • Dry, scaly skin
    • Burning or tingling sensations
    • Blistering, oozing areas of skin

    Symptoms tend to develop within 72 hours of contact with allergens like latex, nickel, poison ivy, and others.

  • How do antihistamines reduce allergy symptoms?

    Antihistamines block a chemical called histamine that is released by the immune system in response to an allergen. Histamine triggers allergy by causing blood vessels to widen and tissues to swell, leading to nasal congestion, red eyes, rash, and other characteristic symptoms. Blocking histamine prevents or reverses these effects, relieving symptoms.

  • What are the signs of a severe allergy?

    A potentially life-threatening, whole-body allergy known as anaphylaxis is recognized by the rapid onset of symptoms, usually within minutes to hours of exposure to an allergen. Call 911 or seek emergency care if you develop any of the following signs of anaphylaxis, including:

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Daniel More, MD
Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and currently practices at Central Coast Allergy and Asthma in Salinas, California.