What is nasal mucus?

The nasal cavity is lined with a thin lining known as the epithelium that has specialized cells which produce and secrete mucus. This nasal epithelium is not significantly different from epithelium lining the rest of the respiratory tract. Mucus is constantly produces to :

  • trap dust particles and microbes
  • moisturize the nasal linings
  • assist with the sense of smell

Mucus in the nasal cavity usually drains into the back of the throat where it unconsciously swallowed in small amounts. Tiny hair-like projections known as cilia also help push the mucus towards the back of the throat. The larger nasal hairs that are visible in the nose are often coated with the nasal mucus. This also helps trapping dust and microbes from the incoming air.

Dried Nasal Mucus

Nasal mucus is a semi-liquid discharge. It is thick (viscous) but still sufficiently fluid to spread out in the nasal cavity and drain into the back of the throat. However, not all nasal mucus drains this efficiently. Sometimes the nasal mucus dries up becoming more of a soft solid mass. This dried nasal mucus is sometimes referred to commonly as ‘boogers’ or ‘crusties’. It is at times visible when it adheres to the nasal hairs close to the opening of the nose (nasal vestibule). This dried nasal mucus can be uncomfortable as the solid masses slightly obstruct the flow of air through the nasal cavity. It often compels a person to remove it manually with the use of a finger – ‘nose picking’.

What causes dried nasal mucus?

Dried nasal mucus is not an uncommon phenomenon. It occurs on a daily basis both for physiological and environmental reasons.

Flowing air has a drying effect. Since air is constantly moving in an out of the nasal cavity, it will inadvertently dry some of the nasal mucus. This is further exacerbated if the air in the environment is very dry, the mucus secretion is excessive or thicker than normal, and if the flow of air through the nasal cavity is faster than is usually the case. Furthermore the mucus traps particles in the air and these particles will also contribute to thickening and drying of the nasal mucus.

These conditions may arise with :

  • Dry climates.
  • Dusty environment – sand, organic and inorganic dusts.
  • Air conditioned areas.
  • Rapid breathing although a person may more often breathe through the mouth in these instances.
  • Dehydration.
  • Runny nose – although the mucus is thinner, it is secreted in excess allowing some to be dried up when drainage is inadequate.
  • Overuse of certain types of nasal sprays that reduces mucus production and secretion.

When there is injury to the nasal lining, usually from nose picking, it may lead to bleeding which gives rise to crusts of bloody nasal mucus.

Hard Nasal Mucus

Dried nasal mucus is largely solidified but still somewhat soft in most cases. However, should it dry up excessively or have collected with large quantities of airborne particles, it tends to form a hard mass. Ar times it can be extremely hard with jagged edges. These harder masses of nasal mucus can injure the nasal lining and lead to bleeding. The blood adheres to the mucus and solidifies. Hard bloody nasal mucus may then be passed out from the nasal cavity when blowing the nose or when picking the nose. Dried pus and the action of bacterial enzymes may also contribute to hard nasal mucus.

What causes hard nasal mucus?

The causes of hard nasal mucus is largely the same as dried nasal mucus but it is usually exacerbated. This includes :

  • Extremely dry climates
  • Very dusty environments
  • Cold rooms and refrigerated storage areas
  • Sudden change in environments like moving from a hot humid country to a cold dry region
  • Nasal infections (infectious rhinitis)
  • Sinus infections (sinusitis)

Rhinoliths

Rhinoliths are stones (calculi) that form in the nasal cavity. It is not just dried nasal mucus or hard nasal mucus. Calcium, magnesium and phosphate salts deposit around a nidus like a blood clot. It gradually grows into an irregularly shaped sphere with projections. Rhinoliths tend to occur on one side only (unilateral) and is solitary. Initially it leads to profuse nasal discharge, sometimes with blood in the discharge, but when it becomes large enough it can cause nasal obstruction. A rhinolith that is left untreated can cause perforation in the nasal septum or sometimes even palate. It can also lead to granuloma formation.

Causes of Rhinoliths

Rhinoliths develop when different salts accumulate around a nidus – any particle that acts as the core which salts can be deposited upon. The stone grows gradually over long periods of time before it becomes symptomatic or leads to complications. The nidus for the development of a rhinolith may be :

  • Blood clot
  • Dried pus
  • Dust particles
  • Cotton wool balls
  • Other small foreign bodies

Article reviewed by Dr. Greg. Last updated on March 11, 2012