Allergy symptoms depend on the type of allergy but may include sneezing, itchy skin, or swelling. Some allergies can cause anaphylaxis, which can be life threatening and requires immediate treatment.
Allergies occur when the body’s immune system overreacts to a substance that would otherwise be harmless. There are many different types of allergies, which may each cause different symptoms.
Pollen allergy is a reaction to one or more types of pollen. Other names for pollen allergy include hay fever and seasonal allergic rhinitis.
Pollen allergy is a seasonal allergy, meaning it tends to occur at certain times of the year. Depending on where someone lives, different pollens may trigger allergies at different times of the year.
People with pollen allergy only experience symptoms when the pollen they are allergic to is in the air. Allergy symptoms that occur at the same time every year may be due to pollen.
Symptoms of a pollen allergy may include:
- a runny or stuffy nose
- sneezing
- red, watery eyes
- swelling around the eyes
- itching of the nose, eyes, ears, or mouth
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A dust mite allergy is a reaction to dust mites or their waste. Dust mite allergies may be
Dust mite allergy symptoms may include:
- sneezing
- a runny or stuffy nose
- postnasal drip, which is where mucus flows from the back of the nose into the throat
- red, itchy, or watery eyes
- itching of the nose, mouth, or throat
- itchy skin
- cough
In some people, dust mite allergy may trigger an asthma attack. These people may experience additional symptoms, such as:
- difficulty breathing
- a whistling or wheezing sound when breathing out
- pain or tightness in the chest
- difficulty sleeping due to shortness of breath, coughing, or wheezing
Food allergies may range from mild to severe, and food that triggers mild symptoms on one occasion may cause more severe symptoms on another.
Food allergy symptoms typically occur within 2 hours of ingesting the allergen, and most of these develop within minutes. Rarely, a person may experience a delayed allergic reaction around 4 to 6 hours later.
Food allergies can be life threatening. Symptoms may include:
- abdominal cramps
- nausea and vomiting
- diarrhea
- coughing or wheezing
- skin rash or hives
- a tingling or itching sensation in the mouth
- swelling of the face, tongue, or lips
- swelling of the throat and vocal cords
- difficulty breathing
- dizziness or lightheadedness
- loss of consciousness
According to the American College of Allergy, Asthma, and Immunology (ACAAI), insect stings are common in the United States, but most reactions are mild to moderate.
Insect sting allergy symptoms may include:
- pain
- itching
- skin redness or other color changes
- swelling in or around the area of the sting
- hives
However, the ACAAI states that between 1.6% and 5.1% of people who get an insect sting in the United States experience a life threatening allergic reaction called anaphylaxis, which requires immediate medical attention.
People can develop allergies to medications, including pills, liquids, and injectable medications. Medication allergies can affect any part of the body. Symptoms may include:
- skin rash or hives
- itching
- swelling
- vomiting
- wheezing
- difficulty breathing
- dizziness or lightheadedness
- anaphylaxis
The ACAAI notes that the following medications are common triggers of an allergic reaction:
- penicillin and related antibiotics
- antibiotics containing sulfonamides
- nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin (Acuprin) and ibuprofen (Advil)
- anticonvulsants
- chemotherapy drugs
Anaphylaxis is a severe, life threatening allergic reaction, typically affecting more than one part of the body. Symptoms usually occur within 5 to 30 minutes of contact with an allergen but can sometimes take more than an hour to develop.
Symptoms of anaphylaxis may include:
- skin rash or color changes, often with itchy hives
- swelling of the throat or other parts of the body
- tightness in the chest
- wheezing
- cough
- hoarse voice
- difficulty breathing
- stomach cramps
- vomiting
- diarrhea
- pale or red skin on the face or body
- a feeling of impending doom
- fainting or loss of consciousness
Anaphylaxis is a medical emergency. Without immediate treatment, it can be fatal.
Someone at risk of anaphylaxis should carry an epinephrine autoinjector, or “EpiPen,” with them at all times.
The ACAAI states that people should self-administer epinephrine as soon as they begin to experience symptoms of anaphylaxis or knowingly come into contact with an allergen.
It is also best to dial 911 and ask for an ambulance, even if they administer epinephrine.
A person should consider talking with a doctor if they believe they or their child may have an allergy. In some cases, a doctor may refer them to an allergist — a physician who specializes in diagnosing and treating allergies and asthma.
Anyone who experiences symptoms of anaphylaxis should call 911 and ask for an ambulance, even if they have self-administered epinephrine.
According to the ACAAI, people who experience anaphylaxis may experience a second anaphylactic reaction up to 12 hours after the initial reaction. Medical professionals call this a “biphasic reaction.”
Both types of anaphylactic reaction can be fatal without immediate medical treatment.
What causes sudden allergy symptoms?
People may develop allergies at any stage of their life, but
Allergy symptoms usually occur immediately after contact with an allergen but may also take longer. Reactions may vary from person to person.
How can someone reduce allergy symptoms?
People with allergies work with a doctor to create an allergy management plan to help manage their symptoms.
A doctor may suggest avoiding or reducing contact with the allergen and may recommend over-the-counter or prescription medications, including antihistamines.
If someone is at risk of a severe allergic reaction, a doctor may recommend carrying an epinephrine auto-injector at all times and using it when the person knowingly comes into contact with their allergen.
What causes constant allergy symptoms?
People may experience constant allergy symptoms if they regularly come into contact with an allergen.
According to the ACAAI, more than two-thirds of people with springtime allergies experience year-round symptoms. This may indicate that someone has allergies to other pollens or other substances, such as mold spores or dust mites.
Allergies occur when the body’s immune system overreacts to a substance that would otherwise be harmless. There are many different types of allergies, and each may be more likely to cause certain symptoms.
Allergies can sometimes cause anaphylaxis, which may lead to swelling of the throat, breathing difficulties, and loss of consciousness. Anaphylaxis is a medical emergency. Anyone with symptoms should call an ambulance immediately.
People should consider talking with a doctor if they or their child experience symptoms of an allergy. A doctor can work to determine the cause and provide appropriate treatments and management strategies.