Nasal irrigation is a common method for relieving nasal congestion and cleaning the nasal cavity, especially suitable for nasal care after allergic rhinitis, colds, or air pollution. However, many people, for convenience, directly use tap water instead of saline solution for rinsing. Unbeknownst to them, this seemingly harmless action may pose hidden health risks. Although tap water is disinfected, its composition differs from the human physiological environment, and misuse can cause irritation, infection, or even more serious consequences.
Chemical Irritation and Mucosal Damage
Tap water contains chlorine, minerals (such as calcium and magnesium ions), and its pH value (usually 7-8.5) does not match the physiological environment of the human nasal mucosa (pH 5.5-6.5). Direct rinsing can damage the acidic protective film in the nasal cavity, leading to dryness, congestion, and even stinging. Long-term use may also weaken the barrier function of the mucosa, making the nasal cavity more susceptible to pathogens. For example, the irritant properties of chlorine may worsen symptoms in rhinitis patients, while high concentrations of minerals may form deposits that clog nasal hair filters and reduce the nasal cavity's self-cleaning ability.
Risk of Microbial Infection
Although tap water is disinfected with chlorine, small amounts of bacteria (such as Pseudomonas aeruginosa and Legionella) or amoebae may still remain in the pipes. These microorganisms can be flushed deep into the nasal cavity during rinsing, especially when the rinsing pressure is too high or the nasal mucosa is damaged. Pathogens are more likely to invade the sinuses or lower respiratory tract, causing infections such as sinusitis and pneumonia. Studies show that the risk of infection after rinsing the nasal cavity with tap water is 3-5 times higher than using saline solution, especially for children, those with weakened immune systems, and patients with sinusitis.
Increased Nasal Sensitivity and Inflammation
The nasal mucosa is extremely sensitive to changes in temperature and osmotic pressure. Tap water is usually colder than body temperature (around 20-25°C). This low temperature can cause vasoconstriction, worsening nasal congestion. Furthermore, its osmotic pressure (around 100-300 mOsm/L) is lower than that of saline solution (308 mOsm/L), classifying it as a hypotonic solution. After rinsing, water may penetrate mucosal cells, causing swelling or even rupture, further exacerbating inflammation. For example, if someone with allergic rhinitis mistakenly uses tap water, their symptoms such as itching and sneezing may worsen, creating a vicious cycle of "the more you wash, the more congested your nose becomes."
Rare but serious complication: Meningoencephalitis
In extremely rare cases, pathogens in tap water (such as Naegleria fowleri) may enter the brain through the nasal cavity, causing primary amoebic meningoencephalitis (PAM). Although rare (less than 1 case per year globally), this disease has an extremely high mortality rate (over 95%). Amoebic protozoa are typically found in warm freshwater (such as lakes or inadequately disinfected swimming pools), but theoretically, infection is possible if tap water pipes are contaminated or if the nasal mucosa is damaged during rinsing. Although cases are rare, they serve as a stark reminder of the importance of using safe rinsing water.
Nasal irrigation is an effective nursing method, but "caution with water" is the key principle. The correct approach is to use a dedicated saline solution (0.9% sodium chloride solution) or isotonic seawater spray, whose composition is similar to human bodily fluids, effectively cleaning the nasal cavity without disrupting the mucosal balance. If you must prepare your own saline solution, use boiled and cooled water or purified water, and strictly follow the recommended ratio (9 grams of salt per liter of water). Furthermore, the water temperature should be close to body temperature (around 37°C), the pressure moderate, and excessive force avoided.
Health is paramount; it starts with the details. Choosing safe rinsing water is the most basic protection for the nasal mucosa and a crucial step in preventing respiratory diseases.
