What are the signs and symptoms of allergy?
The severity and kinds of allergy symptoms depend on a person’s genetics, the allergic condition, and the type and amount of allergens involved.
There are many different types of allergic conditions. An allergic condition is the appearance of allergy signs and symptoms in specific organs or areas of the body. The most common allergy symptoms affect the nose, sinuses, lungs, and eyes. However, in some conditions organs such as the skin, digestive system, and blood vessels can be affected as well.
Not all allergic reactions happen the same way. Some allergy symptoms occur immediately after exposure to an allergen, while others take hours or days. Scientists think that the biological events leading up to immediate allergic reactions are different from those that result in delayed allergic reactions.
Immediate Allergic Reactions
Immediate allergic reactions typically occur within minutes of exposure to an allergen. Allergic reaction time will vary depending on a person’s genetics, and on the site of the body affected.
Delayed or Late-Phase Allergic Reactions
Delayed or late-phase allergic reactions generally occur two to six hours after exposure (and even longer in some people). Signs and symptoms of delayed or late-phase allergic reactions are generally the same as those for immediate allergic reactions.
In the case of allergic asthma, a delayed allergic reaction can cause other problems such as loss of sleep due to nighttime asthma attacks. There are ways to time allergy and asthma medications to reduce symptoms of the delayed allergic response.
Signs and Symptoms of Allergy
For a list of signs and symptoms for different allergic conditions, click on the links below, or just scroll down the page.
Allergic Asthma
Anaphylaxis
Inhaled Allergens (Pollen, Animal Dander, Mold Spores, Dust Mites, Cockroaches)
Ingested Allergens
Insect Venom
Latex
Allergic Skin Conditions
Anaphylaxis
The most serious kind of allergic reaction. Fortunately, it is very rare.
Symptoms usually appear rapidly - within seconds or minutes - after exposure to an allergen, but in some rare cases, reactions have been delayed by as much as 12 hours.
In anaphylaxis, cells in the immune system release large amounts of chemicals - including histamine. As a result, blood vessels open up and begin to leak fluid into surrounding tissues, producing swelling.
Possible Signs and Symptoms of Anaphylaxis on the…
Skin:
Digestive Tract:
- nausea, vomiting, diarrhea
Respiratory Tract:
- swelling of the throat
- wheezing that progresses to severe breathing difficulty
Whole Body (Systemic):
- low blood pressure (hypotension)
- light-headedness
- loss of consciousness
IMPORTANT: SIGNS AND SYMPTOMS OF ANAPHYLAXIS USUALLY APPEAR RAPIDLY. ANAPHYLAXIS IS A LIFE-THREATENING EVENT AND REQUIRES IMMEDIATE PROFESSIONAL MEDICAL ATTENTION. CALL 911 IF YOU SUSPECT ANAPHYLAXIS.
It’s worth repeating that anaphylaxis is rare. The vast majority of people with allergies will never have an anaphylactic reaction.
Learn more about anaphylaxis.
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Common Inhaled Allergens (Pollen, Animal Dander, Mold Spores, Dust Mites, Cockroaches)
Hay fever (allergic rhinitis) and allergic asthma are conditions commonly associated with inhaled allergens. Pollen is more often associated with symptoms of hay fever such as itchy, watery eyes; sneezing; and a runny nose. Mold spores, dust mites, and cockroaches, are more often associated with asthma symptoms such as wheezing and shortness of breath. Animal dander can trigger both rhinitis and asthma symptoms.
Genetics aside, the amount of allergen you are exposed to in large part determines the severity of symptoms. Therefore, an important aspect of treating allergies to an inhaled allergen is to reduce or eliminate the allergen from your environment.
Most signs and symptoms of inhaled allergens appear in the nose, sinuses, eyes, respiratory tract, and occasionally the skin.
Possible Signs and Symptoms of Inhaled Allergens on the…
Nose, Sinuses and Eyes:
- nasal congestion
- sneezing
- runny nose (rhinorrhea)
- itchy, red, watery eyes
Skin:
Respiratory Tract:
- asthma symptoms (coughing, wheezing, shortness of breath)
Learn more about the following inhaled allergens:pollen; mold; dust mites; animal dander.
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Common Ingested Allergens (Food and Medications)
Signs and symptoms of ingested food allergens such as milk, eggs, peanuts, wheat, soy, peanuts, tree nuts, fish or shellfish, can vary extensively depending on a person’s genetics, and on the amount of allergen eaten. Every person does not respond the same way to food allergens, and may experience only one, or many symptoms. It is possible to develop food allergies throughout adulthood, although they more common in childhood.
Anaphylaxis is a possible reaction in food allergy.
Even if immediate signs and symptoms of food allergies subside, they may recur hours later. If they do recur, they may be more, or less severe.
Allergic reactions to medications are complicated. They can be caused by a variety of drug classes and can have a wide range of symptoms affecting virtually any organ or system in the body. Drugs can also have adverse reactions that resemble symptoms of allergy.
Penicillin and other antibiotics are among many medications that can cause allergic reactions.
Anaphylaxis is a possible reaction in medication / drug allergy.
Possible Signs and Symptoms of Food and Drug Allergens on the…
Nose and Sinuses:
- nasal congestion
- sneezing
- runny nose (rhinorrhea)
- itchy, watery eyes
Skin:
Digestive Tract:
- tingling or itching of the lips, tongue, palate, or throat
- swelling of the lips or tongue
- bloating; cramping, nausea or vomiting, and diarrhea
Respiratory Tract:
- chest tightness
- swelling of the throat and hoarseness
- wheezing and shortness of breath (asthma symptoms)
Whole Body (Systemic):
- low blood pressure (hypotension)
- loss of consciousness
- anaphylaxis
Learn more about the following ingested allergens:food; medications / drugs.
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Insect Venom
The severity of symptoms to an insect sting depends on a person’s genetics, the type of venom, and on how much venom is injected.
Insect venom also causes toxic reactions that may resemble symptoms of allergy. A toxic response is due to compounds in the venom itself acting on cells and tissues of the body. Whereas, a true allergic response is a result of the body’s own compounds - such as histamine - that are produced by an over-reaction of the immune system to the venom. Consult your doctor if you are not sure if a reaction to an insect sting is allergic, or toxic. Reactions to insect venom can also be both allergic and toxic.
Allergic responses occurring more than 4 hours after an insect sting are classified as delayed reactions. There have been isolated reports of systemic signs and symptoms occurring up to a week after a sting. People who experience such extremely delayed symptoms are at risk of anaphylaxis to future stings. These people are good candidates for immunotherapy.
Possible Signs and Symptoms of Insect Venom Allergies on the…
Skin:
Respiratory Tract:
- chest tightness and shortness of breath
- wheezing (allergy symptoms)
Whole Body (Systemic):
- low blood pressure (hypotension)
- loss of consciousness
- anaphylaxis
Learn more about allergies to insect venom.
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Latex Allergy
People allergic to latex, or natural rubber, are allergic to a protein found in the rubber tree. Latex is used in all kinds of things like tires, toys, household and medical examining gloves, surgical tubing, and many other items – possibly even the paint in your house. Latex allergy is a major problem for people who work in clinical healthcare. Powder from latex gloves can be inhaled and cause whole body (systemic) reactions, or anaphylaxis.
Possible Signs and Symptoms of Latex Allergies on the…
Skin:
Respiratory Tract:
- chest tightness and shortness of breath
- wheezing (allergy symptoms)
Whole Body (Systemic):
- low blood pressure (hypotension)
- loss of consciousness
- anaphylaxis
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Allergic Skin Conditions
Eczema (Atopic Dermatitis) and Hives (Urticaria)
Allergy symptoms of the skin are most often associated with two conditions: urticaria (hives) andatopic dermatitis (eczema ).
What are the symptoms of eczema?
Eczema or atopic dermatitis, is a fairly common skin disorder associated with allergies. It is most common in infancy and young children. Symptoms may last for months at a time, clear up, and then return.
- Dry, itchy and easily irritated skin that can continue for years and may result in damage to the skin.
Learm more about eczema (atopic dermatitis).
What are the symptoms of hives (urticaria)?
- The appearance of red, itchy, swollen areas of the skin, usually soon after exposure to an allergen, temperature change, vibration, or pressure.
- The hives may be small bumps or large irregularly shaped areas.
Learn more about hives (urticaria).
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This information has been approved by David Tinkelman, M.D. (February 2006).
