Many people wrongly assume that allergies always begin in childhood or young adulthood, since severe food allergies are most common in children. The reality is, a new allergy can develop at any point in life. Adults who never had an allergy before may suddenly begin reacting to food, seasonal changes, medication, insects, pets, or dust mites. Even lifelong allergy sufferers are not off the hook: People who have had allergies since childhood, or who outgrew them, may also develop new ones as adults.
Facing a new allergy in adulthood can feel confusing. It’s not always easy to identify the cause of a new allergic reaction, especially when you haven’t introduced anything new into your life. Once you do identify what is causing your new allergy, you might wonder why it suddenly bothers you. Here, we explore what contributes to adult-onset allergies, and how to treat them.
Adult Allergy Sufferers, You’re Not Alone
Any allergy that begins in adulthood is considered an adult-onset allergy, even if a person has other allergies or has had allergies in the past. Over 26 million adults in the U.S. are estimated to have a food allergy, and 48% of them developed a food allergy in adulthood. Some studies estimate that nearly one-third of all U.S. adults have an allergy of some type.
Adults may develop newly formed allergies to:
- Specific foods, such as shellfish, fish, tree nuts, peanuts, fruits, vegetables, or red meat
- Seasonal allergies to tree pollen, grass, or ragweed
- Pets, including cats, dogs, or rodents, like hamsters and rabbits
- Dust mites, which can also aggravate asthma
- Medications, like antibiotics or non-steroidal anti-inflammatory drugs (NSAIDs)
- Items that touch the skin, like metal, latex, or cosmetics ingredients
- Insect bites, stings, or related microscopic particles
What Triggers New Adult-Onset Allergies?
The number of people with allergies, including adult-onset allergies, has been steadily increasing over the past few decades. The body can develop an allergic reaction to an otherwise harmless substance, and there are multiple potential factors that could play a role in someone developing an adult-onset allergy, including:
- Environmental changes
- Hormonal, immunity, and health changes
- Medication changes
- Dietary changes
- Chemical exposures
- Insect and and stings
In short, change and new exposures of any kind can set off an immunity response that leads to the formation of a new allergy.
Environmental Changes
Environmental changes include any change to a person’s surrounding environment. Moving across the country to a different climate is an environmental change, as is moving down the street into a different house. An individual can also experience an environmental change without moving as the home’s structures degrade with age, or when they introduce a new pet into the home.
Seasonal Allergies That Start In Adulthood
When a person moves to a new region, they are exposed to different plants, sources of dust, and more, which can become new allergy triggers. But new seasonal allergies do not show up overnight. Instead, they usually begin three to five years after moving.
Climate change may also be causing an increase in adult-onset seasonal allergies because it is changing the environments people already live in. Studies show that in North America, allergy season now begins earlier and is 20 days longer than it was in 1990. Daily pollen levels during allergy season are also higher than they’ve historically been. As a result, people who already had allergies may find they are more severe, while those who did not have allergies before may now develop them.
In some cases, developing new seasonal allergies causes a specific type of new food allergy, called oral allergy syndrome, or pollen-food allergy syndrome (PFAS). With PFAS, the body recognizes proteins in certain fruits as similar to those in plants and reacts with an itchy mouth or throat, or swollen lips and tongue. PFAS can happen after a person develops an allergy to birch pollen, ragweed, or grass. Fruits that may trigger a PFAS reaction include apples, melons, bananas, and more.
Indoor Allergens
Adult-onset allergies can also be brought on from change in the home environment. For example, moving into a different house or apartment might trigger allergies if the new home has hidden mold in the basement, walls, or ventilation system. Proteins from the unseen waste of cockroaches or mice in walls can also spread through heating and air conditioning systems. If a home is poorly ventilated or windows aren’t opened often, allergies could develop due to an increase in allergens in the air.
Getting a new pet can also trigger allergies, even in someone who had pets as a child. Living without animals for years may result in a loss of tolerance to them. Cats and dogs often cause allergies with their dander, and different breeds release more dander than others. Other common pets like hamsters, rabbits, and birds may trigger allergies through dust, fur, habitat bedding, and more.
Hormonal, Immunity, and Health Changes
Hormonal changes from perimenopause and menopause can increase low-grade inflammation and dysregulate the immune system, making new allergies more likely in older women. Some studies suggest that hormonal changes in menopause are linked to asthma, food allergies, and skin allergies.
Other aging-related immunity changes may lead to the formation of new allergies. Studies show that 5% to 10% of people over 65 have allergies. Older adults experience immunosenescence, as well as increased inflammation, called inflammaging. Together, these changes can lead to a lower immune response. For some, this may actually decrease allergies, but for others, it may result in developing asthma, skin allergies, insect allergies, or food and drug allergies for the first time.
Medication Changes
A medication change involves starting a new medication or supplement, discontinuing a medication, or changing the dosage of a medication. The most common drug allergies are to penicillin, “sulfa drug” antibiotics, anti-seizure medications, chemotherapy, and nonsteroidal anti-inflammatory drugs, like aspirin and ibuprofen.
Medication can also impact the body in a way that prompts other types of allergies. For example, research suggests that medications that reduce stomach acid may lead to food not breaking down completely, which can trigger new food allergies.
Dietary Changes
Changing what you eat can shake up allergy triggers. For example, not eating something for years and then reintroducing it, for some people, can cause an allergy flare. Changing your diet to include proteins that weren’t previously eaten may also prompt new food allergies.
In some cases, changing one’s diet reveals an allergy that was present, but unknown. This may happen with the previously mentioned pollen-food allergy syndrome (PFAS). A person with seasonal allergies to birch pollen or ragweed may not realize they have PFAS, then begin to experience symptoms after increasing fresh fruit in their diet as part of an attempt to eat healthier.
Strangely, elimination diets may be more likely to lead to a new food allergy among people with eczema or similar skin disorders.
Chemical Exposures
Repeated chemical exposures can make a person more sensitive to certain substances and, over time, can cause an allergy to form. These types of allergies often stem from a person’s job. Chemicals used in factories, nail salons, and hair salons can lead to allergies after a worker is exposed to them daily for months or even years on end. The same is true for people who use cleaning supplies professionally or interact with metals as part of their occupation.
Likewise, a frequent hobby with repeated exposure to something may also cause someone to develop a skin allergy. For example, someone may develop an allergy to paint, the latex in gloves, nickel in metal jewelry or zippers, ingredients in cosmetics or body care products, and more if they use these materials often.
Insect Bites and Stings
People are more likely to develop an allergy to insect venom after repeated exposure. A severe allergy to a wasp, hornet, or yellow jacket sting can appear suddenly, even after years of only minor reactions to stings from the same insects.
Receiving a tick bite, particularly from the lone star tick, can lead to a red meat allergy called alpha-gal syndrome. The tick’s saliva contains alpha-gal, which is found in red meat such as beef. After a bite, the body may start reacting to it and develop an allergy. Some people with alpha-gal syndrome also have reactions to other red meats, like pork, lamb, and game meats.
Allergy Symptoms vs. Sinus Infections and Irritation
Sometimes allergy symptoms can be difficult to distinguish from other symptoms that aren’t caused by allergies, such as a cold, sinus infection, or stuffy or runny nose (nonallergic rhinitis).
| Allergies (Allergic rhinitis) | Stuffy or Runny Nose (Nonallergic rhinitis) | Common Cold (Infectious rhinitis) | Sinus Infection or Inflammation | |
| Primary Cause | Immune system has an allergic reaction to something | Blood vessels in nose swell in reaction to irritants | A viral infection inflames the nose and throat | An infection or blockage causes inflammation in the sinuses |
| Prevalence | Up to 30% of adults | Up to 25% of people | Adults average 2 to 4 colds per year | About 12% of adults |
| Ages Affected | All ages, but commonly begins in childhood | All ages, but commonly begins after age 20 | All ages, but happens more frequently in children | All ages, but chronic symptoms most common after 50 |
| Common Seasons | Spring and summer, though indoor allergies are year round | Fall and winter | Fall and winter | Fall and winter |
| Common Triggers | Pollen, dust mites, animal dander, mold | Weather changes, cold or dry air, smoke, spicy foods, chemical fumes | Exposure to someone who’s sick, touching contaminated surfaces, close contact in large crowds | A recent cold or other respiratory infection, nasal polyps, exposure to irritants |
| Onset | Begins within minutes of allergen contact | Can begin quickly or gradually after contact with an irritant | Begins 1 to 3 days after catching the virus | Begins slowly, often after a lingering cold or allergy flare |
| Duration | As long as allergen exposure continues; days, weeks, or months | Ongoing or flares up in response to irritants | Typically resolves in 7 to 10 days | Acute cases last 10 days to 4 weeks; chronic cases can last 12 weeks |
| Common Symptoms | Itchy nose and eyes, watery eyes, sneezing fits | Stuffy or runny nose, sneezing, post-nasal drip, cough, no itching | Sore throat, sneezing, mild cough, headache, body aches | Facial pain or pressure, nasal congestion, reduced smell, headache |
| Nasal Discharge | Thin, clear, watery | Thin, clear, watery; postnasal drip common | Starts thin and clear, turns thicker, cloudy, or white | Thick, cloudy, yellow or green |
| Oral Antihistamine Effect | Significantly relieves sneezing, itching, and runny nose | Provides little to no relief | Ineffective; does not reduce or shorten symptoms | Ineffective; does not relieve infection or inflammation |
Although allergies, nonallergic rhinitis, the common cold, and sinus infections share similar symptoms, they have very different causes and require different treatments.
Treatments For Adult-Onset Allergies
There are different types of treatment for adult-onset allergies, depending on a person’s needs.
- Antihistamines: Antihistamines are available as oral tablets and as nasal sprays, available both over-the-counter and by prescription. These help relieve itching, sneezing, runny nose, hives, and other allergy symptoms.
- Steroid nasal sprays: Steroid nasal sprays are also available both over-the-counter and in prescription strengths. They work locally in the nose to reduce inflammation and nasal congestion associated with allergies.
- Epinephrine auto-injectors: Epinephrine treats anaphylaxis, a life-threatening allergic reaction. Auto-injectors allow someone to inject themselves in the outer thigh with a pre-measured dose of epinephrine to quickly stop a reaction long enough to seek emergency care.
- Topical creams: When an allergy causes a skin reaction, topical creams may help. Hydrocortisone cream is a commonly used over-the-counter option. Stronger corticosteroid creams are also available by prescription.
- Allergy shots: A healthcare provider gives regular allergy shots to a patient over a long length of time to gradually increase exposure to a specific allergen. After 3 to 5 years of regular treatment, this can greatly reduce its symptoms. Booster shots may be needed for maintenance.
- Biologics: Biologics are a prescription injectable medication usually only used for certain severe or persistent allergic responses that don’t respond to standard treatments.
When To Seek In-Person Care
It’s important to seek immediate, in-person care for allergies when symptoms are severe and appear suddenly. If you have difficulty breathing, swelling in your mouth or throat, sudden or severe hives that are spreading, or a rapid heart rate, use epinephrine (such as an Epi-Pen) right away. Then call 911 or go to an emergency room for follow-up care, even if symptoms seemingly resolve after using epinephrine. These can be signs of anaphylaxis, which is potentially life-threatening.
If symptoms are not severe, but they last two weeks or more, you may want to see a medical professional. A healthcare provider can help you identify what you may be allergic to, as well as the best treatments for your situation. It’s especially important to seek help if your symptoms seem to be worsening over time or they are disrupting your sleep or daily activities.
Finding Targeted Allergy Relief Online
If you have allergies and are familiar with the care you need, consider using a digital pharmacy platform as a convenient way to refill your treatments or renew your prescription without having to wait for a doctor’s appointment. TelyRx offers FDA-approved allergy medications, including the more cost effective generic equivalents of popular brand names. If you need a new prescription, TelyRx can work behind the scenes to connect you with a licensed provider in your state.
But not all digital pharmacy platforms are created equal. Beware of pharmacy scams and prioritize seeking platforms that have clear trust markers. For example, TelyRx boasts LegitScript certification, a catalog of more than 500 FDA-approved medications, HIPAA-level privacy protections, and skilled in-house pharmacists who fill every order from either our pharmacy in Irving, Texas or Clearwater, Florida.
Your Next Steps
If your adult-onset allergy symptoms are severe or disrupting your daily life, seeing a doctor is the best choice to receive a clear diagnosis. If your symptoms are mild, or if you’ve already seen a doctor and you know the underlying cause of your allergic symptoms, filling your prescription from a digital pharmacy platform might just be the most convenient way to find relief.
