Acute Epiglottitis: Although classically associated with sore throat and fever, atypical presentations can occur, especially in adults or in the early stages of the disease. The high rising epiglottis is a hallmark sign.

Laryngopharyngeal Reflux (LPR): Can cause inflammation and edema of the epiglottis without the typical symptoms of sore throat or fever, presenting instead with throat clearing, hoarseness, or a sensation of a lump in the throat.
Allergic Reaction: An allergic reaction could potentially cause swelling of the epiglottis, although this would more commonly be associated with other symptoms such as urticaria, itching, or respiratory distress.
Trauma: Direct trauma to the epiglottis or the surrounding area could lead to swelling and a high rising epiglottis without systemic symptoms like fever.

Epiglottic Abscess: A rare but potentially life-threatening condition that requires immediate attention. It can present with severe respiratory distress and may not always have accompanying fever or sore throat, especially in the early stages.
Cancer of the Epiglottis or Surrounding Structures: Although less common, a tumor could cause a mass effect leading to a high rising epiglottis. This diagnosis is critical not to miss due to its implications for treatment and prognosis.

Angioedema: A rare condition that can cause rapid swelling of the epiglottis and other tissues, potentially leading to airway obstruction. It is often associated with other systemic symptoms or a history of similar episodes.
Relapsing Polychondritis: An autoimmune disorder that can affect cartilaginous structures, including those in the larynx, potentially leading to inflammation and swelling of the epiglottis.
Sarcoidosis: A systemic disease that can affect any organ, including the larynx, causing granulomatous inflammation that might result in a high rising epiglottis.