This chapter discusses laryngotracheal infections and stridor, where acute laryngitis is a viral or bacterial inflammation of the larynx or it may just be a part of upper and lower respiratory tract infections as seen in influenza or common cold. Acute allergic disorders may be seen as a result of drug reaction, local allergic reaction or because of contact mucositis. Scleroma of the larynx is caused by Klebsiella rhinoscleromatis and is treated by steroids. Acute laryngotracheobronchitis is a dangerous infection seen mostly in children which involves tracheobronchial tree. Diphtheria of larynx usually follows faucial diphtheria caused by Corynebacterium diphtheriae. Foreign bodies of larynx are seen less commonly as compared to foreign bodies of digestive tract. Chronic laryngitis is a chronic inflammation of the mucosa of the larynx. Infection by mycobacteria leads to tubercle formation which breaks down forming an ulcer, which may further involve soft tissues and cartilages.