Although mucus normally is swallowed unconsciously, the feeling that it is accumulating in the throat or dripping from the back of your nose is called post-nasal drip.

What Causes Abnormal Secretions – Thin and Thick

Increased thin clear secretions can be due to colds and flu, allergies, cold temperatures, bright lights, certain foods/spices, pregnancy, and other hormonal changes. Various drugs (including birth control pills and high blood pressure medications) and structural abnormalities can also produce increased secretions. These abnormalities might include a deviated or irregular nasal septum (the cartilage and bony dividing wall that separates the two nostrils).

Increased thick secretions in the winter often result from too little moisture in heated buildings and homes. They can also result from sinus or nose infections and some allergies, especially to certain foods such as dairy products. If thin secretions become thick and green or yellow, it is likely that a bacterial sinus infection is developing. In children, thick secretions from one side of the nose can mean that something is stuck in the nose (such as a bean, wadded paper, or piece of toy, etc.).

Sinuses are air-filled cavities in the skull. They drain into the nose through small openings. Blockages in the openings from swelling due to colds, flu, or allergies may lead to acute sinus infection. A viral "cold" that persists for 10 days or more may have become a bacterial sinus infection. With this infection you may notice increased post-nasal drip. If you suspect that you have a sinus infection, you should see your physician for antibiotic treatment.

Chronic sinusitis occurs when sinus blockages persist and the lining of the sinuses swell further. Polyps (growths in the nose) may develop with chronic sinusitis. Patients with polyps tend to have irritating, persistent post-nasal drip. Evaluation by an otolaryngologist may include an exam of the interior of the nose with a fiberoptic scope and CAT scan x-rays. If medication does not relieve the problem, surgery may be recommended.

Vasomotor rhinitis describes a nonallergic "hyperirritable nose" that feels congested, blocked, or wet.

General measures for thinning secretions so they can pass more easily may be recommended when it is not possible to determine whether an existing structural abnormality is causing the post-nasal drip or if some other condition is to blame.

Many people, especially older persons, need more fluids to thin secretions. Drinking more water, eliminating caffeine, and avoiding diuretics (fluid pills) will help. Mucous-thinning agents may also thin secretions.