Croup: This is the most common cause of hoarseness in children, especially when accompanied by fever. Croup is characterized by a barking cough, hoarseness, and sometimes difficulty breathing due to inflammation of the larynx and trachea.

Laryngitis: Inflammation of the larynx can cause hoarseness and is often associated with a viral upper respiratory infection, which could also present with fever.
Pharyngitis: Although primarily causing sore throat, some cases of pharyngitis can lead to hoarseness, especially if the inflammation extends to the larynx.
Bronchiolitis: While primarily causing respiratory symptoms like wheezing and cough, bronchiolitis can sometimes present with hoarseness, especially in younger children.

Epiglottitis: A life-threatening condition that requires immediate medical attention. It involves inflammation of the epiglottis, which can cause severe respiratory distress, hoarseness, and fever. Although less common since the introduction of the Hib vaccine, it remains a critical diagnosis not to miss.
Retropharyngeal Abscess: An infection in the tissues at the back of the throat, which can cause severe respiratory distress, fever, and changes in voice, including hoarseness.

Foreign Body Aspiration: Although more commonly associated with choking or coughing, aspiration of a foreign body can sometimes present with hoarseness if the object irritates the vocal cords.
Laryngeal Papillomatosis: A rare condition caused by the human papillomavirus (HPV), leading to growths on the larynx that can cause hoarseness.
Laryngomalacia: A condition where the tissues of the larynx are soft and floppy, which can cause partial airway obstruction and changes in voice, including hoarseness. It's more commonly diagnosed in infancy but can persist.