Infants and children can have seasonal allergies. However, allergies tend to develop between the ages of 3 and 5 years and are rare in babies.

Seasonal allergies occur because the immune system overreacts to allergens in the air during certain times of the year, such as spring, summer, or fall. It produces antibodies that trigger the release of histamine and other chemicals. This can lead to sneezing, a runny nose, congestion, itchy eyes, and throat irritation.

While allergies can develop at any age, they tend to emerge in childhood and often persist into adulthood.

This article discusses the age at which seasonal allergies typically start and their symptoms, diagnosis, and treatment options.

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Seasonal allergies typically begin in childhood. According to Seattle Children’s Hospital, the average age of onset is 3–5 years of age.

However, children may only develop some of the classic hay fever symptoms later in life. Additionally, symptoms tend to peak in school-age children, teens, and young adults.

It is rare for babies and toddlers under 2 years to develop allergies to pollen. This is because they typically require exposure to pollen over two seasons or more.

If a caregiver notices that the child under 2 years has chronic nasal symptoms, such as runny nose and congestion, it may have a different cause. These causes may include recurrent colds, enlarged adenoids, or an allergy to cow’s milk. Food allergies can begin during a child’s first year of life, but pollen allergies rarely do.

It is sometimes challenging for caregivers to differentiate between allergies and the common cold in infants. They can share symptoms, and babies cannot explain how they feel like older children can.

However, there are some key differences:

  • Fever: Common colds typically develop gradually and can cause a fever. Allergies do not cause a fever.
  • Discharge: Allergies cause a clear, watery nasal discharge. With a cold, the secretions are typically thicker and can be discolored.
  • Itching: This is a hallmark of seasonal allergies. Colds do not cause this issue.
  • Duration: Colds typically do not last for more than several days, but allergies are more persistent. Symptoms may occur seasonally or across the year.
  • Age: Babies under 2 years typically do not experience seasonal allergies, so the symptoms are more likely from a cold. Colds typically do not last more than 1–2 weeks and may occur at any time of the year in infants.

If a parent or caregiver is unsure whether their baby is experiencing allergies or a cold, they can consult a healthcare professional. They can take a history and perform a physical exam to determine the cause of the symptoms.

Symptoms of seasonal allergies in children can vary in severity and may include the following:

  • sneezing
  • runny or stuffy nose
  • itchy or watery eyes
  • nasal congestion
  • mucus at the back of the throat, which doctors call postnasal drip
  • coughing
  • sore throat
  • headache
  • fatigue
  • irritability

In some cases, seasonal allergies can also lead to complications such as sinus or ear infections.

Diagnosing seasonal allergies in children typically involves a physical exam and a review of their medical history. The doctor will ask about the child’s symptoms, including when they occur and if there are any specific triggers, such as exposure to pollen or pets.

They will also ask about the child’s family history of allergies or asthma.

Sometimes, a doctor may recommend allergy testing to determine the specific allergen triggering the symptoms. This may involve skin tests, blood tests, or both.

Treatment and management options for seasonal allergies in children may include a combination of medications, lifestyle changes, and allergy shots. The treatment plan depends on the child’s age and symptoms.

Sometimes, doctors may recommend medications, including antihistamines, which block the effects of histamine and therefore reduce the immune response.

Lifestyle changes can also help manage seasonal allergies in children. This may include:

  • Reducing allergen exposure: Parents and caregivers can do this by keeping windows and doors closed when there is a high pollen count and using air conditioning.
  • Washing bedding: Regularly wash bedding, pillowcases, and stuffed animals to reduce allergen levels.
  • Teaching appropriate hygiene: Parents and caregivers can help children develop hygiene practices such as washing their hands frequently and avoiding touching their faces.
  • Using saline nasal sprays: These flush allergens from the nasal passages.

Infants do not tend to develop seasonal allergies, as they have not received exposure to seasonal allergens for long enough to react to them. This typically takes at least one to two seasons of exposure, so seasonal allergies are more common in children over 3 years old.

Symptoms suggestive of allergic rhinitis in infants are usually the result of another cause, such as frequent colds.