Overview

Hay fever, also called allergic rhinitis, causes cold-like symptoms. These may include a runny nose, itchy eyes, congestion, sneezing and sinus pressure. But unlike a cold, hay fever isn't caused by a virus. Hay fever is caused by an allergic response to a harmless outdoor or indoor substance the body identifies as harmful (allergen).

Common allergens that can trigger hay fever symptoms include pollen and dust mites. Tiny flecks of skin shed by cats, dogs, and other animals with fur or feathers (pet dander) also can be allergens.

Besides making you miserable, hay fever can affect how well you perform at work or school and can generally interfere with your life. But you don't have to put up with annoying symptoms. You can learn to avoid triggers and find the right treatment.

Symptoms

Hay fever symptoms can include:

  • Runny nose and nasal stuffiness, called congestion.
  • Watery, itchy, red eyes.
  • Sneezing.
  • Cough.
  • Itchy nose, roof of mouth or throat.
  • Mucus that runs down the back of the throat, called postnasal drip.
  • Swollen, bruised-appearing skin under the eyes, known as allergic shiners.
  • Extreme tiredness and fatigue, often due to poor sleep.

Hay fever triggers

Your hay fever symptoms may occur year-round or may start or worsen at a particular time of year. These are known as seasonal allergies.

Hay fever triggers include:

  • Tree pollen, which is common in early spring.
  • Grass pollen, which is common in late spring and summer.
  • Ragweed pollen, which is common in fall.
  • Dust mites and cockroach droppings, which are present year-round.
  • Dander from pets, which can be bothersome year-round but might cause worse symptoms in winter, when houses are closed up.
  • Spores from indoor and outdoor fungi and molds, which can be both seasonal and year-round.

Hay fever or common cold?

Symptoms can be similar, so it can be difficult to tell which one you have.

Condition Symptoms Onset Duration
Hay fever Runny nose with thin, watery discharge; no fever Immediately after exposure to allergens As long as you're exposed to allergens
Common cold Runny nose with watery or thick yellow discharge; body aches; low-grade fever 1 to 3 days after exposure to a cold virus 3 to 7 days

When to see a doctor

See a healthcare professional if:

  • You can't find relief from your hay fever symptoms.
  • Allergy medicines don't provide relief, or they cause side effects.
  • You have another condition that can worsen hay fever symptoms, such as nasal polyps, asthma or frequent sinus infections.

Many people — especially children — get used to hay fever symptoms, so they might not seek treatment until the symptoms become severe. But getting the right treatment might offer relief.

Causes

When someone has hay fever, the immune system identifies a harmless airborne substance as being harmful. This substance is called an allergen. The body produces immunoglobulin E (IgE) antibodies to protect against allergens. When the body comes in contact with an allergen, these antibodies signal the immune system to release chemicals such as histamine into the bloodstream. This causes a reaction that leads to the symptoms of hay fever.

Risk factors

The following can increase a person's risk of developing hay fever:

  • Having other allergies or asthma.
  • Having a condition called atopic dermatitis or eczema, which makes skin irritated and itchy.
  • Having a blood relative, such as a parent or sibling, with allergies or asthma.
  • Living or working in an environment that constantly exposes someone to allergens — such as animal dander or dust mites.
  • Being exposed to smoke and strong odors that irritate the lining of the nose.
  • Having a mother who smoked during the first year of life.

Complications

Problems that may go along with hay fever include:

  • Reduced quality of life. Hay fever can interfere with enjoyment of activities and cause you to be less productive. For many people, hay fever symptoms lead to missing work or school.
  • Poor sleep. Hay fever symptoms can keep you awake or make it hard to stay asleep. This can lead to fatigue and a general feeling of being unwell, called malaise.
  • Worsening asthma. Hay fever can worsen symptoms of asthma, such as coughing and wheezing.
  • Sinusitis. Prolonged sinus congestion due to hay fever may increase your risk of getting sinusitis — an infection or inflammation of the membrane that lines the sinuses.
  • Ear infection. In children, hay fever often is a factor in middle ear infection, called otitis media.

Prevention

There's no way to avoid getting hay fever. If you have hay fever, the best thing to do is to lessen your exposure to the allergens that cause your symptoms. Take allergy medicines before you're exposed to allergens, as directed by your healthcare professional.

By Mayo Clinic Staff