Nosebleeds, medically known as epistaxis, are common, especially during colder months. Yes, cold weather frequently triggers nosebleeds. They occur when delicate blood vessels lining the nose rupture, which is usually a minor event that stops quickly. Most nosebleeds are anterior, originating from the front part of the nasal septum, and are generally not a cause for serious concern.
The Direct Link Between Cold Air and Low Humidity
The temperature itself is not the primary cause of nosebleeds, but rather the significantly lower moisture content of cold air. Cold air holds substantially less water vapor than warm air, leading to low absolute humidity outdoors. When this cold, dry air enters the home, indoor heating systems warm it up further without adding moisture. This process dramatically reduces the indoor relative humidity, creating an extremely dry environment inside the nasal passages.
How Dry Air Affects Nasal Passages
The nasal passages are lined with moist tissue called the nasal mucosa, which requires consistent moisture to remain pliable and healthy. A primary function of the nose is to warm and humidify inhaled air before it reaches the lungs. When exposed to dry air, the nasal lining loses moisture rapidly as the body attempts to humidify the air. This desiccation makes the mucosa dry, irritated, and less elastic, causing it to crack and crust.
The anterior nasal septum houses Kiesselbach’s plexus, a dense network of superficial blood vessels that is the source of about 90% of all nosebleeds. When the overlying mucosa is dry and cracked, these fragile vessels are left exposed and vulnerable to rupture. Minor trauma, such as gently blowing the nose, sneezing, or light scratching, can easily break the weakened blood vessel walls and initiate bleeding.
Immediate Relief and Prevention Strategies
If a nosebleed occurs, immediate relief involves controlling the bleeding by applying pressure. Sit down and lean slightly forward to prevent blood from flowing down the back of the throat and causing nausea. Use the thumb and index finger to firmly pinch the soft, fleshy part of the nose just above the nostrils for 10 to 15 minutes.
Prevention strategies focus on increasing moisture in both the air and the nasal passages. Running a cool-mist humidifier in the bedroom, especially during sleep, helps maintain an indoor humidity level between 40% and 60%. To directly moisturize the nasal lining, apply a small amount of petroleum jelly or a water-soluble nasal gel inside each nostril with a cotton swab a few times a day. Using a saline nasal spray several times daily can also help keep the nasal membranes hydrated and less prone to cracking.