Many people frequently report worse allergy symptoms in the rain. Treatments follow most of the standard guidelines for allergies, but you may also want to use a dehumidifier.

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Some people experience worse allergy symptoms on rainy days. This can happen when the damp weather encourages the growth of allergens such as mold and dust mites. It can also happen when rain breaks up pollen into smaller particles and causes it to scatter further.

Allergy medications and steps such as running a dehumidifier can help treat rainy day allergies.

Rain can make some allergies worse. This can include allergies to certain pollens, mold, dust, and grass. When rain falls on these allergens, it can break them up into smaller bits. This leads to easier spreading and can result in worse allergies.

Additionally, allergens such as dust mites and mold grow in damp conditions. Rainy weather can increase the number of these allergens both indoors and outdoors. This can lead to increased allergy symptoms.

Rain also leads to many people spending the day inside. For people with indoor allergies, such as allergies to mold, dust, and pet dander, this can mean more time surrounded by those allergens. This can worsen symptoms, especially if rain leads to an increase in the amount of dust or mold in a space.

Can rainwater cause allergic reactions?

Rainwater can contain toxins and pollutants. The Centers for Disease Control and Prevention (CDC) states that rainwater might contain dust, smoke, asbestos, lead, copper, and other chemicals. Additionally, rainwater may contain viruses, bacteria, parasites, and mold.

Rainwater can cause allergic reactions and even serious illness. Rainwater isn’t considered safe for household use unless it’s been treated and tested. The CDC recommends that people with weakened immune systems exercise additional caution before using rainwater.

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What allergies flare up when it rains?

Certain allergies are more likely to flare up when it rains. This can include:

  • Pollen: Rain prevents pollen from traveling and can be a relief for some people with this common allergy. However, it can also increase pollen exposure when pollen is broken into smaller particles. Pollen counts also sometimes increase significantly right after rainstorms.
  • Dust: Dust mites thrive in humidity and warmth. Rain can increase dust mite numbers and can make symptoms worsen.
  • Mold: Similar to dust, mold grows when it has moisture and warmth. Rain can increase mold both indoors and outdoors.
  • Grass: Heavy rain breaks up grass pollen. This can lead to more free-floating grass pollen in the air, and that can lead to worsened allergy symptoms.

The symptoms of allergies on a rainy day can vary depending on the specific allergy and the person.

Some people might experience a reduction in symptoms when the rain first starts but then see symptoms spike later in the day. This can happen when the broken-up pollen disperses in the air.

It’s common for allergies to include:

Here are some steps you can take to help reduce the symptoms of rainy day allergies:

  • Keep windows shut during rainy weather, especially in allergy season.
  • Monitor the pollen count and mold count in your area.
  • Take allergy medications, such as antihistamines on rainy days.
  • Use saline nasal sprays for symptom relief.
  • Try nasal corticosteroid sprays to manage allergy symptoms.
  • Use a dehumidifier to remove excess moisture from the home.
  • Clean your home regularly to avoid the buildup of dust.
  • Check for any leaks in your roof regularly to prevent excess water that can encourage mold and dust growth.

If your rainy day allergies are severe and over-the-counter treatments don’t seem to help, you may want to make a medical appointment.

A doctor can recommend or prescribe additional options. For instance, prescription immunotherapy injections help some people with seasonal allergies find relief.

Read more about home remedies for allergies.

Rainy days can be allergy days for people with pollen, grass, dust, and mold allergies. This happens when rain causes pollen to break into smaller pieces and spread through the air, or when rainy weather increases the growth of mold and dust mites.

People who experience allergy symptoms on rainy days may find relief by closing windows, running dehumidifiers, and taking allergy medications.