After sniffling and sneezing the whole day, all you wanted was a good night's rest. Unfortunately, your allergies wanted no break of their own.

"Many people suffering from allergies complain about nighttime symptoms," says Dr. Mas Takashima, an ENT doctor at Houston Methodist who specializes in treating nose and sinus issues. "It's a big issue because the last thing you need when you're feeling crummy is to miss out on sleep."

What can you do about allergies at night? Dr. Takashima explains why they occur in the first place, including a surprising culprit that anyone suffering from allergies should keep in mind, and steps you can take to get relief.

Why do my allergies get worse at night?

Believe it or not, even something as simple as a positional change while sleeping can have a big impact on certain allergy symptoms, particularly when mucus is involved.

"When you lay down, nasal secretions drip down the back of the throat, which is called postnasal drip," says Dr. Takashima. "This can be very irritating to the throat, leading to a cough that wakes you up."

Mucus can also pool in your nasal passageways, causing congestion that makes it harder to breathe through your nose. Sleeping with your mouth open all night can lead to dryness that makes coughing even more likely.

The triggers don't stop there.

"We tend to forget how much time we spend in our beds, and what we may not realize is that allergens can be waiting for us there," says Dr. Takashima. "In a humid, moist city like Houston, dust mites are prevalent and can collect in bedding — adding to the pollen we carry in from outside."

We may not get coated with yellow dust like our vehicles do, but any pollen particles that settle on your hair and skin can be transferred to your bedsheets, blankets and pillowcases and remain there until their next wash. This can make for a long time — all night even — you're exposed to these allergens.

It's why Dr. Takashima has some unexpected recommendations that might alleviate your nighttime allergy symptoms.

How to stop allergies at night

Perhaps your allergy relief routine already includes medications to help keep your symptoms at bay. (Related: 5 Tips for Avoiding Seasonal Allergy Symptoms)

But if you're still sneezing, coughing and blowing your nose at night, Dr. Takashima recommends the following steps:

Take a shower. Whether after coming in from outside or just before bed, showering can help wash off any pollen lingering on your skin and hair — reducing the amount transferred to your bedding. A steamy shower may also help relieve congestion. If you can't wash your hair every day, wearing a night bonnet can help keep the pollen contained as you sleep.

Wash bedding regularly. Keeping blankets, sheets and pillowcases clean can reduce the amount of time you're exposed to dust mites and pollen that may have settled in your bed. Take care to handle bedding gently, so you don't disperse allergens into the air when readying it for the wash.

Rinse your sinuses before bed. Sinus irrigation, also called sinus rinse, can help clear the nose of pollen and other allergens causing swelling or mucus production. There's no limit to how many times you can rinse your sinuses per day — just be sure to use sterile water, such as distilled water, bottled water or water that's been boiled and allowed to cool to a safe temperature.

Use an air purifier with a HEPA filter. Having a HEPA (high-efficiency particulate air) filter in your bedroom can help reduce allergens. Many of today's air purifiers come equipped with these filters, which trap small, harmful particles, such as pollen, pet dander, smoke and dust mites.

If you still struggle with nighttime allergy symptoms despite taking over-the-counter medication and employing these tips, Dr. Takashima says it may be time to see a doctor.

"When allergies are interfering with your quality of life, we start to consider prescription medications and allergy testing," says Dr. Takashima. "Your doctor can also help rule out other potential causes of your symptoms, such as a sinus infection or another health issue."