**Question:** All are true about Cancrum Oris except:

A. It is an infection caused by Nocardia asteroides.
B. It is limited to the oral cavity and jaw.
C. It is a complication of severe malnutrition.
D. It is a rare condition in developed countries.

**Core Concept:** Cancrum Oris, also known as Noma, is a severe necrotizing infection and tissue destruction of the oral and orofacial region, typically in children with malnutrition. It is caused by Nocardia asteroides, a gram-positive bacteria.

**Why the Correct Answer is Right:** The correct answer (D) is right because Cancrum Oris is not limited to the oral cavity and jaw. It is a rare condition in developed countries, but it remains a significant health problem in developing regions where malnutrition is prevalent.

**Why Each Wrong Option is Incorrect:**

A. Nocardia asteroides is a causative agent of Cancrum Oris, not the infection itself. It is a group of bacteria that could lead to this condition.

B. Cancrum Oris is not limited to the oral cavity and jaw. It affects the entire orofacial region, including lips, gums, tongue, soft tissues, and bones.

C. Although malnutrition is a predisposing factor and complicates the clinical presentation and management of Cancrum Oris, it is not a unique characteristic of the condition. Cancrum Oris can occur in immunocompromised individuals or in those with uncontrolled diabetes.

**Clinical Pearl:** Cancrum Oris is a severe orofacial infection of children with malnutrition, often presenting as a triad of necrotic lesions, ulcers, and gangrene. Prompt diagnosis and treatment are crucial to prevent complications like sepsis and deformity.