Rhinorrhea

# Overview
Rhinorrhea, commonly known as a runny nose, is a symptom of the common cold and  allergies (hay fever).  The term comes from the Greek words "rhinos" meaning "of the nose" and "rhoia" meaning "a flowing." Rhinorrhea can also be a sign of withdrawal, such as from opioids. Symptoms display circadian rhythms.
Cerebrospinal fluid rhinorrhea can indicate basilar skull fracture.

# Overview
Nasal discharge is any mucus-like material that comes out of the nose. Nasal discharges are common, but rarely serious. Drainage from inflamed or infected sinuses may be thick or discolored.  Excess mucus production may run down the back of your throat (postnasal drip) or cause a cough that is usually worse at night. A sore throat may also result from excessive mucus drainage.   The mucus drainage may plug up the eustachian tube between the nose and the ear, causing an ear infection and pain. The mucus drip may also plug the sinus passages, causing sinus infection and pain.

# Causes

## Common Causes
- Common cold
- Flu
- Allergies
- Hay fever
- Sinusitis
- Head injury
- Bacterial infection
- Foreign body
- Nasal spray

## Causes by Organ System

## Causes in Alphabetical Order
- Acetylandromedol
- Acute upper respiratory infection
- Adenoiditis
- Adenoviridae infections
- Aesculus pollen
- Africanized honeybee
- Airborne allergy
- Alder tree
- Allergic irritability syndrome
- Allergic rhinitis
- Allergic tension-fatigue syndrome
- Allergy-like conditions
- Alternaria
- Amaranthus
- American feverfew
- Amylcinnamic alcohol
- Anaphylaxis
- Andromedotoxin
- Animal allergy
- Anisyl alcohol
- Ant
- Anthrax
- Apomorphine
- Aromatic amino acid decarboxylase deficiency
- Ash juniper tree pollen
- Ash tree
- Aspergillus
- Asrar-facharzt-haque syndrome
- Atrophic rhinitis
- Aureobasidium
- Autonomic dysreflexia
- Baby's breath poisoning
- Basilar skull fracture
- Beech tree
- Beet
- Bent grass
- Benzyl alcohol
- Benzyl salicylate
- Bermuda grass
- Birch tree
- Bird allergy
- Bird flu
- Black fire ant
- Bluegrass
- Bog rosemary poisoning
- Box elder tree
- Brain injury
- Bronchiolitis
- Bronchitis
- Bronchopulmonary dysplasia
- Bumblebee
- Caffeine allergy
- Canary allergy
- Canary grass
- Candida albicans
- Capeweed
- Carcinoma
- Cat allergy
- Catarrh
- Caterpillar complication poisoning
- Charlin's syndrome
- Chemical addiction
- Chemical allergy
- Chemical poisoning
- Chicken allergy
- Chlorine
- Chloroacetophenone
- Chronic infections
- Chronic pneumonitis of infancy
- Chronic rhinitis
- Chronic sinusitis
- Cigarette smoke allergy
- Ciliary dyskinesia
- Cinnamic alcohol
- Cinnamic aldehyde
- Cladosporium
- Clomethiazole
- Cluster headache
- Coastal leucothoe poisoning
- Cocaine abuse
- Cocaine addiction
- Cocklebur
- Cockroach
- Codeine withdrawal
- Common cold
- Congenital nasal abnormality
- Coronavirus-related cold
- Coumarin
- Coxsackievirus-related cold
- Crack addiction
- Cs gas
- Cypress tree
- Daisy
- Dandelion pollen
- Diabetes
- Dilaudid withdrawal
- Dog allergy
- Dopamine beta-hydroxylase deficiency
- Drug allergies
- Duck allergy
- Dust mite allergies
- Eaf
- Echovirus
- Egg hypersensitivity
- Elm tree
- English plantain
- Enterovirus
- Ephedrine
- Epicoccum
- Esthesioneuroblastoma
- Eugenol
- European ash tree
- Fetterbush poisoning
- Florida leucothoe poisoning
- Flu
- Food additive allergy
- Food allergies
- Foreign body
- Fungal infection
- Fusarium
- Gabapentin
- Geraniol
- Glutaraldehyde
- Goose allergy
- Goosefoot
- Granulomatosis with polyangiitis
- Grass pollen allergy
- Grayanotoxin
- Greenhead ant sting
- Guanethidine
- Guayule
- H1n1 flu
- Hay fever
- Hazel tree
- Head injury
- Helminthosporium
- Hemosiderosis
- Hemp
- Heroin withdrawal
- Hickory tree
- Honey bee
- Honey intoxication
- Hop shrub
- Hornbeam tree
- Hornet
- Horse chestnut tree
- House dust allergy
- Hydrocodone withdrawal
- Hydroxycitronellal
- Hypersensitivity reaction
- Hypothyroidism
- Ige mediated gastrointestinal food allergy
- Immotile cilia syndrome
- Inch ant sting
- Isoeugenol
- Jack jumper ant sting
- Japanese andromeda poisoning
- Johnson grass
- Juvenile angiofibroma
- Kartagener syndrome
- Kentucky bluegrass
- Latex allergies
- Leprosy
- Lortab withdrawal
- Lymphomatoid granulomatosis
- Malignant teratocarcinosarcoma
- Maple tree
- Marsh elder
- Mastocytosis
- Measles
- Metapneumovirus
- Methadone withdrawal
- Methyldopa
- Methyldopate
- Midline lethal granuloma
- Mold allergy
- Monteroy pine tree
- Morphine withdrawal
- Mountain andromeda poisoning
- Mountain cedar tree
- Mountain laurel poisoning
- Mucocutaneous leishmaniasis
- Mucopolysaccharidosis type i hurler-scheie syndrome
- Mucor
- Mucormycosis
- Mugwort tree
- Muscarine
- Musk ambrette
- Nasal cancer
- Nasal foreign body
- Nasal mastocytosis
- Nasal obstruction
- Nasal papillomas
- Nasal polyp
- Nasal tumor
- Nasopharyngeal carcinoma
- Nasopharyngitis
- Nasopharynx cancer
- Nettle
- Nitrogen dioxide inhalation
- Oak moss absolute
- Oak tree
- Occupational cancer
- Occupational lung disease
- Olea tree pollen
- Olive tree
- Opioid addiction
- Opioid withdrawal
- Orache
- Orchard grass
- Organophosphates
- Orthomyxovirus
- Otitis media
- Oxycontin addiction
- Ozone inhalation
- Pain killer addiction
- Parainfluenza
- Parakeet allergy
- Paramyxovirus
- Parrot allergy
- Patterson's curse
- Pecan trees
- Penicillium
- Percocet withdrawal
- Perennial rhinitis
- Perfume
- Periorbital cellulitis
- Pernettya poisoning
- Pet allergy
- Phentolamine
- Phoma
- Phosgene inhalation
- Phosgene oxime exposure
- Pigeon allergy
- Pigweed
- Plane tree
- Plantago pollen
- Polychondritis
- Poplar tree pollen
- Prescribed medication addiction
- Primary ciliary dyskinesia
- Pulmonary anthrax
- Ragweed
- Rapeseed oil
- Rasagiline
- Recurring airway infection
- Red fire ant
- Redroot
- Redtop grass
- Relapsing polychondritis
- Reserpine
- Respiratory syncytial virus
- Respiratory tract infections
- Rhinitis medicamentosa
- Rhinocerebral mucormycosis
- Rhinocerebral zygomycosis
- Rhinosporidiosis
- Rhinovirus
- Rhizopus
- Rhodotoxin
- Rice millers' syndrome
- Rodent allergy
- Rosai-dorfman disease
- Rubella
- Ryegrass pollen
- Sagebrush
- Sandalwood oil
- Sarcoidosis
- Scorpion
- Seafood allergy
- Serratia respiratory tract infection
- Sheep laurel poisoning
- Single upper central incisor
- Sinonasal undifferentiated carcinoma
- Sinus infection
- Sinusitis
- Skull fracture
- Slap-cheek syndrome
- Sleeping pill addiction
- Smut
- Sorrel
- Sparrow allergy
- Sphenoid sinusitis
- Spice allergy
- Spicy foods
- Stachybotrys chartarum
- Staggerbush poisoning
- Stress incontinence
- Sulfur dioxide inhalation
- Sunct headache
- Sunflower pollen
- Sweet chestnut tree
- Sweet vernal grass
- Swine flu
- Syphilis
- Systemic capillary leak syndrome
- Teething
- Tilia tree pollen
- Timothy grass
- Ting kung teng
- Tonsilitis
- Toxic mushrooms
- Tranquilizer addiction
- Tree pollen
- Trilostane
- Tropical fire ant
- Tubatoxin poisoning
- Tuberculosis
- Tumble weed
- Turkey allergy
- Type a influenza
- Type b influenza
- Type c influenza
- Type i hypersensitivity
- Upper respiratory tract infection
- Urinary incontinence
- Vasomotor rhinitis
- Velvet grass
- Vicodin withdrawal
- Wall pellitory
- Walnut tree
- Wasp
- Wegener's granulomatosis
- White cedar tree
- Whooping cough
- Willow tree pollen
- Wood tar
- Yellow jacket wasp
- Zotepine
- Zygomycosis

# Treatment
Keep the mucus thin rather than thick and sticky. This helps prevent complications, such as ear and sinus infections, and plugging of your nasal passages. To thin the mucus:
- Drink extra fluids.
- Increase the humidity in the air with a vaporizer or humidifier.
- Antihistamines may reduce the amount of mucus. Be careful, because some antihistamines may make you drowsy.
- Use saline nasal sprays. Don't use over-the-counter nasal sprays more frequently than three days on and three days off, unless ordered by the doctor.