What Causes Allergies? Could It Be Something Else? (podcast)

The different types of allergies, their symptoms and treatments

Dr. Ronald Simon is an allergist at Scripps Clinic.

Dr. Ronald Simon, Allergy and Immunology, Scripps Clinic

The different types of allergies, their symptoms and treatments

Allergic reactions come in many forms — waking up sneezing on pollen-heavy days, breaking out in hives after inadvertently consuming nuts, gastrointestinal issues after taking penicillin-based medication and other situations. According to the Centers for Disease Control and Prevention, allergies to foods, animals, environmental factors, medications and other substances trigger nearly 17 million doctor visits each year.


In this episode of San Diego Health, host Susan Taylor interviews Ronald Simon, MD, an allergist and immunologist at Scripps Clinic Carmel Valley. Dr. Simon explains how the term “allergies” has become a way to describe something we dislike or are intolerant to, and how several conditions mimic the symptoms of an allergy, but true allergies are caused by the immune system reacting to a natural substance that’s harmless to most people. Tests can differentiate allergies from other conditions.


Genetics predispose some people to certain allergies, though they may not ever develop them. It’s possible to outgrow allergies you had as a child. Avoiding whatever you’re allergic to is one course of preventive treatment, but it’s not always possible. Over-the-counter or prescription medications can help too. Immunotherapy, or gradually desensitizing a person to whatever they’re allergic to, is also an option.

Podcast highlights

Listen to the episode on allergies, what they are and treatments

Listen to the episode on allergies, what they are and treatments

What are allergies? (0:58)

Let’s start with what’s not an allergy because so many people think they’re having allergies when they’re really not. It’s become almost an English word, not even a medical word. People think that something that is repugnant to them, something they just don’t agree with, that they’re allergic to it. I remember people talking about even being allergic to Mondays.


There are also intolerances, both in the English language and in medicine, such as lactose intolerance. There are sensitivities that are really not exactly allergies, so we differentiate them in a medical sense.


An allergy involves the body’s immune system. That’s primary and foremost. That means that only certain people actually have them. Irritants bother everybody, so if there’s enough smoke around, everybody is going to start coughing and sneezing. But with an allergy, it’s an exquisitely little amount of something that sets off the body’s immune system. So, cigarette smoke is an irritant. That’s not an allergy. But something like a flower, or a food, or an animal that is a natural substance and should be harmless in a medical sense, when the body’s immune system starts to react to tiny little exposures of it, it can be triggering a typical allergy reaction.

What are the most common types of allergies? (2:20)

Foods, things in the air, flowers, pollens, dust mites, animals and medications.

What types of food would prompt an allergic reaction? (2:35)

It would be things like wheat and soy, milk and eggs, fish, including shellfish, and nuts.

Is gluten intolerance an allergy? (3:03)

That’s a great example of what is not exactly an allergy. Sometimes you call it gluten intolerance, and many people think they have that, and probably do, but we actually have no test for that. There is a much smaller group of people who are gluten sensitive, and they have a very distinct medical disorder for which there is a test, but they’re a very small minority of people. But none of those really are the same as being gluten or wheat allergic.

What are environmental allergies? (3:33)

Pollens. Depending upon the season, it could be grasses, trees, or weeds, molds, and that could be either seasonal or in somebody’s home.


We talk about dust allergy, but when you think of dust particles floating in the air, those are just debris. You really can’t be allergic to that. They can be irritating, and a lot of people may sneeze if they’re around a lot of dust, but it’s not exactly an allergy. Allergy to dust is actually something called dust mites. They are microscopic but living creatures, and like every living creature, they live where their food source is. They eat dead flaky skin. They would live in pillows and mattresses where our dead skin would tend to collect.

Can we be allergic to our pets? (4:34)

People come to us all the time and say, well it’s not my dog because it’s hypoallergenic. Or, it’s not my cat; it’s everybody else’s cat. So, two different explanations. For years, everybody thought they had these hypoallergenic dogs, and finally, a group did a research study. They vacuumed up the dust in homes that had regular standard dogs, and they vacuumed up the dust from homes that had hypoallergenic dogs. They measured the dust for dog allergen, and the levels were identical because it’s not the fur or the dander that’s actually the allergen. It’s actually secretions and excretions, saliva, things like that, that get on the fur and the dander, and then when it is shed, it’s carrying it. The allergens are part of being a dog or a cat.

What are medication or drug allergies? (5:22)

Any medication can cause an allergic reaction. Penicillin is one of the most common, antibiotics in general, aspirin and all the aspirin related medicines, such as ibuprofen. Even insulin, something that seems so natural, is something you can have an allergic reaction to.

What are metal and cosmetic allergies? (6:08)

It happens. It involves a whole different part of the body’s immune system than we’ve been talking about. We call it a delayed hypersensitivity.

What other conditions mimic the symptoms of an allergy? (6:23)

Intolerances are one. Somebody who is lactose intolerant, they’ll eat dairy and get terrible cramps, and even have diarrhea, which is not an unusual food allergy symptom, but it has nothing to do with being allergic to dairy. It’s actually a lacking of an enzyme.


We mentioned irritant reactions. Somebody who’s around a lot of cigarette smoke, can have an irritant reaction. It’s not really an allergen. But the symptoms can be the same with sneezing, coughing and congestion.

Who is most affected by allergies? (7:24)

It can be anybody, but definitely children have it most often. But it is not unusual, and it can certainly happen that an adult of any age can develop an allergy for the first time. But it is definitely more common in children.


Some of the things that put you at risk is your genetics. If there is a family history of allergy, then it’s more likely that you can have allergies. But what’s really important is that it’s not a specific allergy that you inherit, just the potential to be allergic. We hear stories about somebody saying, I want to be tested to insect stings, or penicillin, because my father or mother or brother or sister was allergic to it, and that’s not the case. You develop an allergy to what you’re exposed to, not something that you’ve never been exposed to, but if your family just has an allergic background, then you’re more likely to have some allergy.

Can you outgrow a childhood allergy? (8:11)

Absolutely. Fortunately it happens very frequently with foods. We mentioned how wheat and egg and soy are among the most common food allergies. You can hardly find an adult who’s allergic to any of those three for reasons that nobody understands. The nuts and fish persist, but definitely you can outgrow that, and then you hear about a lot of people that had terrible hay fever when they were younger, even terrible asthma when they were younger, and now that they’re an adult, it’s just totally disappeared.

How do you really know when it’s an allergy? (8:45)

Think about what you’re being exposed to. If it’s something in the air, then you’re going to have symptoms in the places where it goes. You have ocular symptoms. Your eyes will be itchy and water. If it goes into your nose, you’ll be sneezing. In an allergic reaction, the body is trying to get rid of what it’s reacting to, so your nose will run; you will sneeze to try to get rid of it. Your nose congests to prevent any more from going in. If it gets into your lungs, you can start to cough and wheeze and get short of breath. It’s going to be somewhat different for a food because it doesn’t go there; it goes into your mouth. The first symptoms should be maybe itching inside the mouth, maybe a little bit of swelling. But then when you swallow the food and it goes into your stomach, you may get an upset stomach, nausea, maybe even vomit. But then it goes into your intestines, and you may get cramps and abdominal pain and bloating, even diarrhea. Then after that, maybe if the food can make it through the intestine into your bloodstream, then you can start to get what we call systemic complaints, and that can be itching, developing hives, which are raised red itchy welts, even getting giant swelling. It can also go to the respiratory tract and produce the same symptoms that the airborne allergens do.

What’s the difference between a cold and allergies? (10:04)

It can be hard to tell, but usually colds have a season, and it’s usually the winter season, which is not the allergy season, because nothing is really growing and pollinating during the winter. Usually when kids go back to school, a lot of times the colds will start. That can be harder to differentiate because there are some late summer and early fall allergens. Symptoms can be very similar, but one thing that is absolutely part of an infection would be a fever. You don’t always get a fever with a cold, but if you have a fever, it can’t be allergy. The one thing that comes out during allergic reactions that won’t come out with a cold or any other infection, is histamine. Histamine causes itching. If your nose is itchy, your eyes are itchy, if there's itching involved, then you also know it’s not a cold.

What can you do to control your allergic reaction? (10:57)

Well, we like to think about avoidance. If you can avoid it, then you won’t have an allergic reaction. We do teach patients a number of techniques for avoiding a number of allergens, what you can’t avoid. There are medications. These days we have amazingly effective medicines that have no side effects, and many of them are now over-the-counter at full prescription strength. If that’s not enough, or if somebody really wants to no longer be bothered by allergies, we have various ways of desensitizing patients. We call it immunotherapy. We try to tweak their immune system to actually stop reacting.


For pollens, it’s interesting that the time when pollen is going to be the highest is actually in the morning. So, if you want to go do some exercise, maybe just time it to a different part of the day. If it’s really bad and you stay indoors, an air conditioning filter will actually filter out about 85 percent of the pollen. If you have a HEPA filter, it gets almost all of the pollen, so that will work. For furry animals, it’s a little bit more difficult. Nobody wants to give up their animals, and I totally get that. But you would at least like to make the bedroom kind of a sanctuary because you spend so many hours in there, and not have exposure. So, the animal could just be out of the bedroom.

How do allergy drugs work? (12:31)

For most of those histamine symptoms that we were talking about, the itching, and watering, and sneezing, you can take an antihistamine. These days, what I call the big three, which for many, many years were only by prescription, are now full strength over-the-counter.


By brand name there is Claritin, which is a loratadine; there is Allegra which is fexofenadine, and Zyrtec which is cetirizine. Amazingly effective, some people may get a little bit drowsy with cetirizine, Zytrec, but most people handle it very well. The other two are really non-sedating. Now, they don’t work very well on congestion. If your nose is blocked, you can’t breathe well through your nose. Each of those anti-histamines comes in a D form; the D stands for decongestant, and they basically are adding something like Sudafed. Everybody knows what Sudafed is. That can be very helpful, but Sudafed can kind of make people a little bit anxious, and excited and nervous. You have to watch out for that, especially watch out in the evening.


What have been shown to be the most effective medicines, either used year-round, or during the season, are topical, nasal steroid sprays. They’re now over-the-counter at full prescription dose. There are three or four of them that are out there, and they control basically the whole allergic reaction. Used regularly, they can be amazingly effective. One drawback though is that if you are congested, the spray won’t go in. So you need to do something to make room for it, and we have various ways of doing that.

What is an allergy shot? (14:08)

There is something that’s called an allergy shot, without the S for plural, that people have kind of gotten used to. And that really is a steroid shot. I was mentioning they have these over-the-counter nasal steroid sprays. Steroids are just the most powerful anti-inflammatory medicines that we have. They are the best for allergic inflammation. Some people who live in places where allergies are seasonal, when they’re miserable, they go see their doctor, and their doctor just gives them an injection of a steroid, and it just carries them right through the season. It normalizes their symptoms within a couple of days, and it just carries them right through the season. That wouldn’t work year-round because taking steroids into your system can have side effects. But for occasional acute exacerbations, seasonal exacerbations, they are amazing.


As allergists, we also give something that’s called allergy shots, with an S, or immunotherapy. That’s actually a program that begins with weekly injections, and then the interval widens, of the very things that the patient is allergic to. A lot of people want something more natural. There couldn’t be anything more natural than the things we’re already inhaling. Getting it as an injection, over a period of time and it’s a five-year program, you can actually control somebody’s allergies that way. Then you stop the shots; they’re off their medications, and they just really feel like they don’t have allergies anymore.

How do you test for allergies? (15:31)

We have something that’s called a nasal smear. We take a little mucus sample from somebody’s nose and look at it under the microscope. The microscopic picture is different for an allergy or an infection or for an irritant. From there, we know what we’re dealing with. We can go on to additional testing for the specific allergen.


For many years, it was little tiny pin pricks with each individual allergen, and then we look at the reaction to that. If somebody has a rash, then we’re trying to figure out what kind of rash it is. We can actually do what’s called the skin biopsy, and take a very tiny little piece of skin and look at that under the microscope. For cosmetics and metals and things like that, we do what’s called patch testing. There, you put a little bit of the substance on the skin, cover it with something like a Band-Aid, and then look at it over the next few days to see if there is any reaction underneath that.

How do you test for a food allergy? (16:20)

Food allergies would be either by skin testing those little skin pricks, or the blood test. For a while, we were doing some patch testing for the foods, but it just hasn’t really worked out as well as we had hoped.

Can spring allergies last longer in places like San Diego? (16:35)

Exactly, it’s a trade off because we hear people coming from other areas, where they had horrible, horrible seasons, but the season was two weeks. Then they come to San Diego, and the seasons never get that bad. That’s good, but they’re also always miserable. There’s almost no time in San Diego that we don’t have some pollen. It seems that the most common thing for people to react to in San Diego pollen-wise is grass pollen, and that can start in San Diego even in January or February, like it did this year with all the rains, and it can go sometimes even until November. There’s almost no time of the year that you’re not affected by it.

If over-the-counter drugs aren’t working, when should you see your doctor for allergies? (17:16)

Sometimes we can just give you some hints about how to make drugs work better. If your nose is really congested, you could spray all you want, and it may not work. But what if it turned out that you were allergic to something like dust mites, and all it would take would be a few avoidance maneuvers? Then you would be fine. You would be off medication. If medication is not working, if you’re kind of curious to know what you’re allergic to, if you just don’t want to deal with allergies anymore, I’m thinking about allergy immunotherapy, or those allergy shots.


There’s a new treatment called sublingual immunotherapy. It’s only available now for three things, grass pollen, ragweed and dust mites. If those happen to be your allergies, you can actually get the medication from a pharmacy. All you do is put a little tablet of the medicine under your tongue every day. Over a period, you hope to get desensitized to those things.

Watch the video on allergies

Watch the San Diego Health video with host Susan Taylor and guest Dr. Ronald Simon, discussing the different types of allergies, their symptoms and treatments.