The right itis for your sob story

In the language of the human bodily systems, understanding of a few suffixes is sufficient to enable one to describe their health status. The suffix is critical in conveying the nature and severity of your sob story to the multitudes. Misuse of these terms might trigger an influx of floral bouquets and hot meals, when the appropriate response would have been a simple hmm, or oh dear. It is usually not one's intention to bamfoozle when misappropriating these, but appreciating their subtlety will get you far in this world of complaining.
ITIS: It is the most recognisable of the family. It is the most inflammatory, angry and self-inflated suffix used in description in medicine. It denotes an inflammatory condition, which is anything under two weeks old usually, although can become chronic or persistent after sticking around. Powerful enough to drive some to medicate, but transcendent enough to leap outside of human involvement to afflict Mondays. There is no treatment for Mondayitis as it is unclear what part of Monday is actually inflamed.
In popular culture, several examples of itis usage demonstrate the callous misuse of the term as disease entity, rather than inflamed part, organ or tissue. Ratititis, as proffered by Roald Dahl, involves eating liquorice bootlaces made of rats blood which caused a rats tail to shoot out of the victim's bottom, and their teeth become rat fangs. Surely you also see the ignorance of the author who clearly should be using ratfangogenesis, or ratomorphism.
Boneitis was a fatal disease of our future in Futurama, where death occurred by sudden contortion of bone. Not a shred of inflammation here. Very disappointing Hollywood.
OSIS: Osis is a statement of the diseased condition of the host body. It is therefore less likely to be used as a made up excuse for a body part injury such as heartosis, liverosis and brainosis. Not only do these not exist, but sound implausible to the untrained ear. They embrace a larger picture of illness and bring power to non specificity. Think Halitosis , Psychosis or Myxomatosis if that sick day needs some dramatic emphasis.
OPATHY: Not to be mistaken for O'Pathy, which could have Gaelic meaning, or apathy which is induced by too much Facebook, opathy suffixes anatomical structures and suggests that there is something pathologically wrong. Usually longer standing dysfunction is the case here and may take some time to settle, unlike the itis. The greek word Pathos is the root here and means "feeling, suffering or a distressed state".
IASIS: Originally Greek for healer, but the Latin retasked it to mean essentially the same as opathy although some sources amplify it by adding morbid to the condition. You might think of Psoriasis, Candidiasis or Elephantiasis.
ALGIA: A condition that has the main ingredient of pain. Tennis Elbow, moving into the hi tech years has evolved into Lateral Epicondylalgia, but can be interchanged with Extensor Tendinosis.
Tendon best encapsulates the difficulty in choice clinicians have faced over the recent years. Originally, we assumed all tendon problems Tendonitis. The mid portion of the Achilles tendon often appears swollen or bulbous, so accompanied by some redness and sharp pain from the benevolent clinician's pincer squeeze, ITIS was the way to go. Later however, someone noticed that there aren't many of the chemicals you'd expect to see in an ITIS, so we moved to either TendinOSIS (a noninflammatory condition involving a previously injured tendon that heals with weak collagenous fibres, low weight-bearing resistance, and a high risk of future injury) or TendinOPATHY (a general term for tendon damage involving overuse, microtears and collagen degeneration, manifested by inflammation, pain and weakness).
Having succumbed myself to an opportunistic infection this week, an Otitis Externa if you will, I lay there between thumping Algias and Throbbing Itises pondering the best descriptors of my pain. Thankfully cytoneogenesis and apoptosis were brought back into balance and apart from sporting Kieran Read's left cauliflower ear, I had witnessed the power of healing, with a little help from modern medicine. I had in my story telling the most appropriate suffixes for everyone I told, and now you too have a cheat sheet to know what I am talking about.