Hay fever, otherwise known as seasonal allergic rhinitis, is an allergic reaction to airborne substances such as pollen that get into the upper respiratory passages – the nose, sinus, throat – and also the eyes. It affects around one in four people. Symptoms that may be caused by the allergy are: itching eyes, sneezing, nasal stuffiness, nasal congestion and drainage, and sometimes headaches.Hay fever usually occurs in spring and summer, when there is more pollen in the air. Trees, grass and plants release pollen as part of their reproductive process. Mould and fungi also release tiny reproductive particles, called spores.People with hay fever can experience their symptoms at different times of the year, depending on which pollens, spores or dust mite are causing the allergy.The human body has its own humidification process that protects the respiratory system. Every time a person takes a breath, the nose, pharynx (behind the nasal cavities and mouth) and trachea (in the throat) add moisture to the air so that it does not dry out. As the air passes further into the airway, it becomes warmer and more humid. By the time it reaches the lungs it is at the ideal temperature and humidity. When you exhale, your nose conserves moisture by recovering about a third of the water present in each exhaled breath.This moisture is then used to humidify the next inhaled breath. With allergies and colds the nasal passages may be blocked causing people to breathe through their mouths and therefore the natural humidification through the nose, which is responsible for two-thirds of humidification, is bypassed. This starts a vicious circle because nasal symptoms trigger mouth breathing and mouth breathing aggravates nasal symptoms.Heated humidification with CPAP greatly decreases the symptoms of nasal congestion, dry nose and throat. The humidifier replaces moisture in the nasal cavity which has been lost due to mouth breathing.Sometimes nasal stuffiness due to rhinitis, sinusitis, or allergies can be relieved by prescription nasal sprays or medications. These may make it easier to breathe during CPAP treatment. However, many patients have found that they can discontinue the use of nasal medications either after changing to heated humidification or after adjusting their humidifier to the proper level to relieve the dryness of the nasal and oral cavity.The benefits of humidification for allergy sufferersWithout humidification, your nose has to work extra hard to warm all the extra air from your CPAP machine and produce even more fluid to maintain moisture levels while also clearing out allergens. This can lead to congestion and inflammation caused by allergies.Additionally, your nose might continue to overproduce fluid for up to three hours after it's needed, known as nasal reactive syndrome. This can make allergy symptoms even worse.By humidifying your CPAP air, you can help alleviate the burden on your nose. This allows it to stay moist without extra effort and clear allergens more efficiently, ultimately reducing congestion and inflammation.If you're someone who experiences seasonal allergies, it's important to speak to an equipment supplier or doctor about how to use and change humidification settings as needed. This will ensure you experience all of the benefits of humidification without experiencing any discomfort from rain-out.Tips for controlling your allergic symptoms:Use hypoallergenic filters with your humidifierKeep windows and doors closed during heavy pollen seasons.Rid your home of indoor plants and other sources of mildew.Change feather pillows, woollen blankets, and woollen clothing to cotton or synthetic materials.Enclose mattress, box springs, and pillows in plastic barrier cloth.Use antihistamine and decongestant as necessary with medical advice.Observe general good health practices; exercise daily, stop smoking, avoid air pollutants, eat a balanced diet, and supplement diet with vitamins, especially vitamin C.