Laryngotracheitis (Croup): This condition is the most common cause of inspiratory stridor in children, characterized by inflammation of the larynx and trachea, often due to viral infections. The presentation of inspiratory stridor, hoarseness, and a barking cough, especially in a child, makes croup a leading diagnosis.

Foreign Body Aspiration: This is a common and potentially life-threatening condition, especially in young children, where an object is inhaled into the airways, causing obstruction. Symptoms can include sudden onset of stridor, coughing, and cyanosis.
Epiglottitis: Although less common due to vaccination, epiglottitis remains a significant concern, particularly in adults or unvaccinated children. It involves inflammation of the epiglottis, which can lead to airway obstruction, presenting with stridor, severe sore throat, and difficulty swallowing.
Angioedema: This condition involves rapid swelling of the dermis, subcutaneous tissue, mucosa, and submucosal tissues, which can lead to airway obstruction if it affects the larynx or tongue. It can be allergic or non-allergic in nature.

Anaphylaxis: A severe, life-threatening allergic reaction that can cause airway constriction, leading to stridor and cyanosis, among other symptoms like rash, hypotension, and gastrointestinal distress. Prompt recognition and treatment with epinephrine are crucial.
Retropharyngeal Abscess: A serious infection in the space behind the pharynx, which can cause airway obstruction. Symptoms include stridor, difficulty swallowing, high fever, and neck stiffness.
Trauma to the Neck or Larynx: Any injury that compromises the airway can lead to stridor and cyanosis. The mechanism of injury and clinical presentation are key to diagnosing this condition.

Laryngeal Papillomatosis: A rare condition caused by the human papillomavirus (HPV), leading to benign tumors on the larynx, which can obstruct the airway and cause stridor.
Subglottic Stenosis: A narrowing of the airway below the vocal cords, which can be congenital or acquired, leading to stridor and respiratory distress.
Vocal Cord Paralysis: Unilateral or bilateral paralysis of the vocal cords can cause stridor, especially if bilateral, due to the inability of the vocal cords to move apart during inhalation.