General Medical Terms

-itis

Meaning of -itis: The commonest ending in the whole vocabulary, and the one most often misread as proof that an infection is present.

Definition of -itis

The suffix -itis marks inflammation of the structure named by the root in front of it. Arthritis is inflammation of a joint, dermatitis of the skin, hepatitis of the liver. Inflammation is the body's response to injury of any kind, so the ending describes what the tissue is doing rather than what set the process off.

What does inflammation actually involve?

A standard response the body mounts wherever tissue is damaged or threatened. Small blood vessels widen and leak, immune cells arrive, and chemical signals build up in the area. The result is the classic set of changes visible on the surface: redness, heat, swelling, pain, and reduced use of the part. On an internal organ the same process shows up as tenderness, altered function, or a raised marker in the blood rather than as anything visible. That whole picture is what inflammation means, and it is the only claim the ending makes.

Does the ending mean an infection?

No, and this is the misreading that matters most. Infection is one trigger among several. Injury, autoimmune attack, allergy, chemical irritation, crystals and long-term wear all produce inflammation without any organism involved. Arthritis is a good illustration, since the great majority of joint inflammation has nothing infectious about it. Contact dermatitis is a reaction to something touching the skin. Where infection genuinely is the cause, the term is usually qualified, as in septic arthritis or bacterial meningitis.

How does it attach to a root?

Directly, with no linking vowel, because the ending itself begins with a vowel. That is why the stomach root gives gastritis rather than gastroitis, and why the joint root gives arthritis rather than arthroitis. Roots ending in a consonant sometimes gain a letter for pronunciation, which is how tendon becomes tendinitis. Almost every organ and tissue in the body has a term built on this pattern.

Term	Root	What is inflamed
gastritis	gastr, stomach	the stomach lining
hepatitis	hepat, liver	liver tissue
bursitis	burs, cushioning sac	a sac near a joint
tendinitis	tendin, tendon	a tendon
colitis	col, colon	the lining of the large bowel

Terms built on -itis

53 entries in this glossary use this word part. Each one follows the same pattern.

acute bacterial prostatitis Inflammation of the prostate gland that begins suddenly and gets worse quickly.
appendicitis An obstructed appendix becomes a closed space under rising pressure, which is what makes…
arthritis A disease that causes inflammation and pain in the joints.
asymptomatic inflammatory prostatitis Inflammation of the prostate gland where the only symptom is the presence of white blood…
autoimmune thyroiditis An autoimmune condition of the thyroid gland (a gland located beneath the larynx).
bronchitis One word covers a self limiting cough after a virus and a lasting change in the airways…
bursitis Pain that worsens with joint movement, along with local swelling and warmth, are hallmark…
carcinomatous meningitis A serious problem that may occur in cancer in which cancer cells spread from the original…
cellulitis Redness appearing on both legs at once is rarely cellulitis, since the infection almost…
chronic bacterial prostatitis Inflammation of the prostate gland that is caused by a bacterial infection and that…
colitis The word describes what the lining of the colon looks like, leaving the cause behind it…
conjunctivitis Conjunctivitis, or pinkeye, inflames the membrane covering the white of the eye and inner…
dermatitis Where a rash sits is often the strongest clue to its cause, since contact reactions trace…
diverticulitis Inflammation of one or more pouches or sacs that bulge out from the wall of a hollow…
duodenitis Duodenitis is inflammation of the first segment of the small intestine, often sharing the…
endocarditis Endocarditis is inflammation of the heart's inner lining and valves, most often from…
esophagitis Inflammation of the esophagus (the tube that carries food from the mouth to the stomach).
folliculitis The giveaway is the pattern: every bump sits on a hair, which separates it from skin…
gastritis Gastritis is inflammation of the stomach lining that can cause upper abdominal…
gastroenteritis Inflammation of the lining of the stomach and the intestines.
Hashimoto thyroiditis An autoimmune condition of the thyroid gland (a gland located beneath the larynx).
hepatitis One word covering many diseases: the letter attached to a viral hepatitis says far more…
laryngitis Laryngitis causes hoarseness or voice loss when the vocal folds swell, most often from a…
leukemic leptomeningitis A serious problem that may occur in leukemia.
leukemic meningitis A serious problem that may occur in leukemia.
lymphomatous leptomeningitis A serious problem that may occur in lymphoma.
lymphomatous meningitis A serious problem that may occur in lymphoma.
mastitis Mastitis is breast tissue inflammation most common during breastfeeding, though its…
meningitis Inflammation of the meninges (three thin layers of tissue that cover and protect the…
mucositis Mucositis most often affects the lining of the mouth and digestive tract, commonly…
neoplastic meningitis A serious problem that may occur in cancer in which cancer cells spread from the original…
nephritis Not one disease but a family of them, sharing inflamed kidney tissue and a set of clues…
osteoarthritis Calling it wear and tear undersells it, since cartilage cells actively dismantle their…
osteomyelitis Osteomyelitis is a bone infection that can arise from bloodstream spread, direct injury,…
pancreatitis Inflammation of the pancreas.
peritonitis Contamination of a normally sterile space, across a membrane broad enough that bacteria…
phlebitis Redness, warmth, swelling, and tenderness along a vein, most often in the leg, are the…
pneumonitis Pneumonitis is inflammation of lung tissue from a noninfectious cause, distinct from…
polymyositis An inflammatory disease of the muscles closest to the center of the body.
polyneuritis An older label for damage affecting many nerves at once, kept mainly where inflammation…
precancerous dermatitis A skin disease marked by scaly or thickened patches on the skin and often caused by…
proctitis Proctitis is inflammation of the rectal lining that can produce pain, bleeding, and a…
prostatitis Prostatitis is inflammation of the prostate gland that can cause pelvic pain, urinary…
radiation dermatitis A skin condition that is a common side effect of radiation therapy.
radiation enteritis Inflammation of the small intestine caused by radiation therapy to the abdomen, pelvis,…
rectitis Inflammation of the mucous membrane that lines the rectum (the last several inches of the…
regional enteritis Chronic inflammation of the gastrointestinal tract, most commonly the small intestine and…
rheumatoid arthritis Stiffness that is worst on waking and eases with movement is the pattern separating it…
sinusitis Nearly every case starts as an ordinary cold, and the newer name rhinosinusitis records…
tendonitis Tissue from painful tendons usually shows disorganized collagen rather than inflammatory…
thrombophlebitis The name splits into three parts, clot, vein and inflammation, and all three are present…
thyroiditis One name covering several unrelated illnesses, united only by an inflamed thyroid and by…
tonsillitis White patches on inflamed tonsils are widely read as proof of a bacterial cause, though…

Also known as

itis

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Used in a sentence

The suffix -itis at the end of the term identified the finding as inflammation of the joint lining.

Good to know

An -itis term states that a tissue is inflamed and says nothing about the cause, so it covers injury, autoimmune attack, allergy and crystal deposits as readily as infection.

Word origin

Where “-itis” comes from

The ending is Greek, a feminine adjective form that once agreed with nosos, meaning disease; arthritis began as a phrase meaning joint disease, and the noun was later dropped.