Allergies are exaggerated immune responses to environmental triggers known as allergens. Allergies are very common, and about 50 million people in North America suffer from allergies. One of the most common forms of allergy is allergic rhinitis ("hay fever"), which produces symptoms like
- nasal congestion,
- itchy and watery eyes,
- stuffy or runny nose,
- scratchy or sore throat,
- throat clearing,
- cough from postnasal drip.
The symptoms of hay fever can, in turn, lead to fatigue and lethargy. Other types of allergic reactions can involve the skin (hives and itching). Anaphylactic shock is a severe form of allergic reaction that can be life-threatening. In anaphylactic shock, there is swelling of the throat and difficulty breathing. Asthma is also related to allergies in many cases.
The symptoms of allergies can sometimes resemble those of other conditions. The common cold and the flu can cause respiratory symptoms similar to allergies. Typically, allergy symptoms are associated with a specific time of year or exposure to an allergen.
Causes of allergies
Allergies result from an inappropriate or misguided reaction to foreign substances (usually harmless substances). Allergens are the substances that trigger allergies. Pollens are the allergens that cause hay fever, one of the most common types of allergic reaction.
A review of our Patient Comments indicated that many people with allergies have similar symptoms and signs. Oftentimes, an allergy attack began with itchy eyes followed by facial swelling, particularly of the eyes and lips. Some patients mentioned that the itchiness occurred all over their bodies, and sometimes they developed hives. Several people indicated that their symptoms felt flu-like, in that they experienced coughing, fatigue, and the sensation that they had a fever. Read on to learn more about allergy symptoms in our Patient Comments.
- Nasal Congestion
- Reddened Skin
- Runny Nose
- Scratchy Throat
- Shortness of Breath
- Swelling of the Throat
- Watery Eyes
Pictures, Images, Illustrations & Quizzes
10 Worst Cities for Spring Allergies With Pictures
See pictures of the top 10 "spring allergy capitals", according to the Asthma and Allergy Foundation of America (AAFA). From...
Allergies Quiz: Symptoms & Home Remedies
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Allergies: 10 Ways to Reduce Mold Allergies
WebMD shows you 10 ways to fight the fungus and reduce mold allergy symptoms from dust masks to bottles of bleach.
Allergies: Common Plants and Trees That Trigger Allergies
Find out more about which plants and trees might be producing pollen that is causing your itchy eyes and a runny nose.
Allergies: Myths and Facts About Seasonal Allergies
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Could I Be Allergic? Discover Your Allergy Triggers
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Dangerous Allergies: Anaphylaxis and Life-Threatening Allergy Triggers
Common allergy triggers may provoke anaphylaxis. Hives, tongue swelling, face swelling, rashes, low blood pressure, rapid and...
Home Allergy Quiz: Is Your Home Allergy-Proof?
Take this home allergy quiz and test your knowledge on allergens, dust mites, pollens and more to see how allergy-proof your home...
Nasal Allergy Attack: Causes, Triggers, Treatments
Nasal allergies are a common problem that affects millions of people. An allergist can recommend the best allergy nasal sprays...
Nasal Irrigation: Natural Relief for Cold & Allergy Symptoms
Clogged sinuses and congestion bothering you? Nasal irrigation can relieve sinus symptoms associated with colds and allergies....
Out-of-Control Allergy Symptoms: Treatment Relief in Pictures
Learn 10 signs your allergies are out of control. See these surprising allergy symptoms and find out how to get relief for...
Picture of Allergic Contact Dermatitis
A red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign....
Picture of Allergic Contact Dermatitis (Arm)
Allergic contact dermatitis (reaction to temporary tattoo). Contact allergy to temporary tattoos has become an increasingly...
Picture of Allergic Contact Dermatitis (Tattoo)
Contact allergy to temporary tattoos has become an increasingly common phenomenon. See a picture of Allergic Contact Dermatitis...
Picture of Allergic Reaction to Lipstick Tattoo
Some people develop allergic reactions to tattoo pigments -- especially red pigments. See a picture of Lipstick Tattoo Allergic...
Picture of Eye Allergies
Severe allergic eye symptoms can be very distressing and are a common reason for visits to the allergist or ophthalmologist. See...
Picture of Tattoo Allergic Reaction
Exuberant blistering reaction in red tattoo pigment. See a picture of Tattoo Allergic Reaction and learn more about the health...
Pictures of Allergy Relief Tips at Home: AC Filters, Electronic Air Cleaners, and More
Learn how a combination of medication, preventing allergens, and allergy relief products can reduce allergy symptoms and help you...
Preparing for Severe Allergies at School
Help your child manage and prepare for severe allergies at school. Protect your child from food allergies, insect stings, and...
The Most Common Food Allergies for Kids and Adults
What common food allergens cause the most problems for adults and children? See this list of common food allergies and learn to...
Top 13 Ways to Tame Eye Allergies
Eye allergies, or allergic conjunctivitis, cause itchy eyes and other allergic symptoms. Avoiding allergens and using medicated...
When Animal (Allergies) Attack: Pet Allergy Symptoms, Treatment
How do you control and relieve pet allergies? How do you prevent pet allergies? Learn dog and cat allergy symptoms, the cause of...
Examples of Medications for Allergy
- Adrenaclick (epinephrine)
- Arcalyst (rilonacept)
- cetirizine (Zyrtec, Zyrtec Allergy, Zyrtec Hives)
- Claritin (loratadine) vs. Zyrtec (cetirizine)
- diphenhydramine, Benadryl
- Does Immunotherapy Work for Allergies?
- Dymista (azelastine hydrochloride and fluticasone propionate)
- fexofenadine (Allegra, Mucinex Allergy)
- loratadine and pseudoephedrine (Alavert Allergy & Sinus, Claritin-D, Claritin-D 24 hour)
- loratadine, Claritin, Claritin RediTabs, Alavert, Claritin Hives Relief, Children's Claritin
- Ondansetron (Zofran) vs. promethazine (Phenergan)
- Quzyttir (cetirizine)
- Side Effects of Claritin-D (loratadine/pseudoephedrine)
- Side Effects of Periactin (cyproheptadine)
- Symjepi (epinephrine)
- Vistaril (hydroxyzine) Side Effects, Warnings, and Interactions
- Xyzal (levocetirizine dihydrochloride)
- Zetonna (ciclesonide)