Many people develop seasonal allergies later in life. New allergies may be triggered by factors such as environmental changes or changes in medications, but the reasons for this are not fully understood.

Seasonal allergies, a type of allergic rhinitis, happen when a person has an allergic reaction to pollen. A person may be allergic to many different types of pollen including tree, grass, and weed pollens.

Allergic reactions occur when the immune system mistakes a harmless allergen for something that could cause illness. Common symptoms of seasonal allergies include sneezing, coughing, irritated eyes, congestion, and itchy throat.

Read on to learn more about developing seasonal allergies as an adult.

Several people lying on grass in a field.Share on Pinterest
Tim Clayton/Corbis via Getty Images

It is common for seasonal allergies to start during early spring and last until early summer. However, seasonal allergies may occur at different times depending on geographic location and the type of pollen a person is allergic to.

Many environmental factors may affect when someone experiences seasonal allergies. However, the most prevalent pollen allergies and when they are likely to cause symptoms are:

  • Tree pollen: February–May
  • Grass pollen: April–June
  • Weed pollen: August–November

Weather can often have an impact on when someone may have allergy symptoms in several ways. For example, rain can reduce the amount of pollen in the air, while wet soil may increase the number of mold spores.

It is not uncommon to develop a new allergy as an adult. However, it is not always possible to know the specific reason an adult develops a new allergy.

Sometimes an allergy that appears to be new can actually be pre-existing. For example, if a person moves to a new area with higher pollen counts than their previous location, their allergy may be exacerbated.

This can also happen when a person stops taking certain medications.

Allergies are usually treated with a type of medication called antihistamines. However, antihistamines are also used to treat other conditions, such as anxiety and insomnia. If a person stops taking one of these, they may discover they are experiencing new allergy symptoms that are no longer being controlled by medication.

It is possible to develop an entirely new allergy later in life, but the reasons for this are not fully understood.

Changes in the immune system, family history, and environmental changes are all thought to be factors in developing new allergies later in life.

Sometimes, a person’s allergies can go away or diminish over time. It is fairly common for children to outgrow certain food allergies, but this is less common for seasonal allergies.

In some cases, repeated exposure to an allergen can promote tolerance. Immunotherapy is one example of this. However, repeated exposure through the skin or respiratory tract may promote an allergic reaction over time.

However, it does not mean that symptoms will not return in the future.

There are several treatment options available for seasonal allergies. These include pills, nasal sprays, and topical treatments.


People can use certain medications to treat or prevent seasonal allergy symptoms that can be accessed over the counter or with a prescription. They include:

  • Antihistamines: These medications block a chemical called histamine, which causes many allergy symptoms. They are available over the counter in pill, liquid, and dissolvable tablet form. One nasal antihistamine, Astepro, is available over the counter, but others are prescription only.
  • Nasal corticosteroids: This is a nose spray that reduces allergic inflammation. Nose steroids are an effective medication for alleviating a stuffy and runny nose.
  • Oral corticosteroids: These medications are sometimes used for severe symptoms caused by seasonal allergies, such as severe swelling. A healthcare professional should monitor the use of this medication as it can cause serious side effects.
  • Mast cell stabilizers: This medication blocks the body from producing histamine and relieves common seasonal allergy symptoms. They are available as both nose sprays and eye drops. However, they are rarely used in clinical practice.
  • Decongestants: These medications reduce swelling in the nose and can help with stuffiness. They are available as both pills and nose sprays. However, it is important to note that using decongestants for more than a few days may cause a rebound reaction, where the swelling returns once stopping them.

Learn more about medications for seasonal allergies.


Immunotherapy is a preventive treatment for allergic reactions. It involves introducing increasing amounts of an allergen to the body to help the immune system become less sensitive to the substance.

This is most commonly done through allergy shots, known as subcutaneous immunotherapy (SCIT). It can also be placed under the tongue, which is known as sublingual immunotherapy (SLIT), or allergy drops.

According to the United States Food and Drug Administration (FDA), the usual course of SCIT involves 32 weekly injections, also known as “build-up” doses. After this, SCIT is administered monthly for 3–5 years.

Unlike other treatments for seasonal allergies, immunotherapy has been shown to provide lasting remission from allergy symptoms.

Learn more about immunotherapy for allergies.

If a person thinks they may be developing seasonal allergies later in life, they may want to speak with a healthcare professional.

A doctor can help identify which allergen is causing a reaction and offer guidance on how to manage the symptoms. Discussing treatment options with a healthcare professional may help reduce the impact of seasonal allergies on a person’s daily life.

It is fairly common to develop seasonal allergies later in life. This may be due to being exposed to new allergens, stopping certain medications, or changes in the immune system.

However, the reasons for developing new allergies are not fully understood.

Individuals can manage and prevent seasonal allergy symptoms with several medications.