Influenza (the flu) is a highly contagious respiratory illness affecting the nose, throat, and lungs, often causing fever, body aches, and significant congestion. While a nosebleed (epistaxis) is not a primary symptom of the flu, the infection creates conditions that make the nasal passages highly susceptible to bleeding. The flu can cause epistaxis, but the mechanism linking the two is typically indirect.
The Direct Connection
The influenza virus triggers a systemic inflammatory response, including in the delicate lining of the nasal passages. This inflammation causes the small blood vessels, known as capillaries, near the surface of the nasal mucosa to swell and become fragile. The irritation and swelling mean these vessels are more easily damaged and prone to rupture, which is the immediate cause of the nosebleed.
Nosebleeds during illness often originate from the anterior nasal septum, a region rich in vessels known as Kiesselbach’s plexus. Flu congestion forces individuals to blow their nose repeatedly and with greater force than usual. This mechanical stress puts traumatic pressure on the compromised capillaries. This act often triggers the final break in the weakened vessel wall, initiating a bleed.
Fever contributes to systemic dehydration during a flu infection. Dehydration causes the nasal lining to dry out and lose its natural protective moisture and elasticity. When the mucous membrane becomes dry, it can crack and fissure, exposing the underlying fragile blood vessels.
The environment often exacerbates this drying effect, especially during colder months when flu activity peaks. Indoor heating systems reduce humidity levels, drawing moisture away from the nasal passages. This combination of illness-induced dehydration and environmental dryness creates an optimal environment for the nasal mucosa to become brittle, making capillaries susceptible to bleeding even without forceful blowing.
Home Management and Prevention
If a mild nosebleed occurs, the immediate response involves applying direct pressure to the nasal septum. The proper technique is to sit upright and lean slightly forward to prevent blood from dripping down the throat, which can cause nausea or vomiting. Using the thumb and forefinger, firmly pinch the soft, flexible part of the nose, specifically below the hard, bony bridge, and maintain this pressure continuously for at least 10 to 15 minutes.
Preventative measures focus on maintaining the moisture and integrity of the nasal lining. Increasing fluid intake, particularly water and electrolyte solutions, helps combat the systemic dehydration caused by fever. Adequate hydration keeps the body’s mucous membranes, including those in the nose, moist and resilient, which is a simple defense against cracking.
Using a cool-mist humidifier, especially overnight, introduces moisture into the dry indoor air, counteracting central heating. This helps prevent the nasal passages from drying out and cracking, reducing the risk of a spontaneous bleed. Additionally, using an over-the-counter isotonic saline nasal spray several times a day can directly lubricate the nasal mucosa and reduce irritation from the viral infection.
Individuals must practice gentle nasal hygiene while congested to minimize mechanical trauma to the inflamed vessels. Instead of aggressive blowing, gently clear the nose one nostril at a time, or simply dab the nose with a soft tissue. Minimizing physical stress on the inflamed capillaries prevents the rupture of fragile blood vessels.
When to Seek Medical Attention
While most flu-related nosebleeds are minor and managed at home, certain signs indicate the need for professional medical evaluation. A primary concern is a nosebleed that persists despite applying continuous pressure for 20 minutes or longer. Prolonged bleeding suggests a more significant vessel may be involved or that underlying clotting issues could be present, requiring intervention like chemical cautery or nasal packing.
Excessive blood loss is another warning sign, particularly if the amount is substantial enough to rapidly soak tissues or clothing. If the bleeding appears to be flowing down the back of the throat even when leaning forward, this may indicate a posterior nosebleed. Posterior bleeds typically involve larger, higher-pressure vessels deeper in the nasal cavity and often require specialized treatment in an emergency setting.
Frequent or recurrent nosebleeds, such as those occurring daily or multiple times weekly, require consultation with a healthcare provider. Recurrent bleeding may point to an underlying anatomical issue, such as a deviated septum, or a coagulopathy unrelated to the flu itself.
Seek immediate medical care if the nosebleed is accompanied by symptoms like dizziness, lightheadedness, or fainting, as these are signs of significant blood loss or circulatory distress. Difficulty breathing or choking due to blood flow are also serious indicators requiring emergency attention.