Rhinitis
The recently published Journal of Allergy and Clinical Immunology had an update on rhinitis. Rhinitis incorporates two Greek words: rhinos, meaning nose, and itis, meaning disease or inflammation. The condition falls into two categories; allergic rhinitis or non-allergic rhinitis. The former is pretty straightforward in that it is caused primarily by airborne allergens such as pollen, dust mites and animal dander but to a lesser degree (and not quite as obviously) due to food allergy. Despite the nasal focus of the name, the condition itself often impacts other connected structures including the sinuses, the eyes, the ears, and the lungs (where the most common feature is cough).
Non-allergic rhinitis (NAR) includes a diverse parcel of conditions. One of the most common is non-allergic rhinitis with eosinophils (NARES) which is a quirky condition. It has all the symptoms seen in allergic rhinitis and is caused by eosinophils (the white blood cells that cause allergies) but the individuals have no positive test responses to any type of allergens.
Another type of NAR is infectious rhinitis which can be either acute or chronic. The acute form is typically caused by cold viruses. The latter form is often caused by chronic colonization of the nose with bacteria or fungus.
Cerebrospinal fluid rhinorrhea is another cause for NAR. What happens here is that a tear or rent in the meninges (the fabric covering of the brain and spinal cord) allows cerebrospinal fluid to slowly leak out of the nose. The tear in the meninges can occur from surgery or from an injury such as a motor vehicle accident or a fall. If not properly diagnosed, it could lead to meningitis.
Vasomotor rhinitis is another NAR that is a bit peculiar. It’s a kind of neuropathy of the nose in that, the autonomic nerves subserving nasal function misbehave. Since all bodily functions including nasal functions are under neurologic control mishaps can occur. It’s important for our brain to micro-manage nasal function so we can adapt and live in the diverse global and climatic conditions of our planet.
People living in the Gobi Desert need their nose to produce lots more mucus than inhabitants of the Brazilian rain forest. With proper neural control the nose adapts properly. But in vasomotor rhinitis the adaptation is both hyperbolic and sometimes inappropriate. Going from a cool house to a warm outdoors, or having the air conditioner kicking on, or going from a darker room to a brighter lit room shouldn’t cause the nose to congest and run profusely, but in vasomotor rhinitis it does.
A variation on the vasomotor theme is gustatory rhinitis. This too is a “neuropathy”. In this case the nose runs every time the individual eats (regardless of the meal content). Gustation
means to taste. What happens here is that as the individual is tasting (eating) food the normal messaging from the brain is to properly digest the food. Unfortunately, it also includes a totally unnecessary messaging to the nose “to run”.
Atrophic rhinitis is one of the few conditions where the nose doesn’t run. In fact, the main problem is nasal dryness which leads to chronic congestion. Often there will be scabs that develop in the nostrils. These individuals have a paucity of mucus glands in the nose. It can develop from living or working in very dry environments. It can also occur from repeated nasal/sinus surgery with removal of too much of the mucus membranes.
Drug-induced rhinitis is definitely a mixed-bag. But many drugs exert their effect by impacting the sympathetic or parasympathetic nerves that control nasal function. Examples include: clonidine, methyldopa, sildenafil, risperidone, lisinopril, amlodipine, and oxybutynin. Still a myriad of other drugs can cause rhinitis including eye drops, female hormones and oral contraceptives, gabapentin and other drugs used for treating neuropathy. A particularly severe form of drug-induced rhinitis is due to over use (with resultant addiction) to topical decongestants such as Afrin and 4-way nasal sprays.
Although it’s not a drug per se, alcohol can often produce rhinitis symptoms including congestion and nose running. Alcohol exerts its effect because it’s a vasodilator (dilates blood vessels). As in all things, some individuals are more alcohol sensitive than others. Asians are particularly prone to this buffeting. Also, people with the facial skin condition rosacea are often more alcohol sensitive.
Finally, there is hormonal rhinitis. Some women’s noses are impacted by changing levels of hormones as seen during the monthly cycle or during pregnancy. Other endocrine conditions can also cause rhinitis most commonly hypothyroidism and acromegaly.