A patient has inflamed, painful gingiva with a fetid odour. What is the diagnosis?

Correct answer: A. Necrotising periodontal disease

• A. Correct. Punched-out, cratered interdental papillae with a grey pseudomembrane, pain and a distinctive fetid odour make the diagnosis. Stress, smoking, poor hygiene and immunosuppression are the usual predisposing factors.
• B. Desquamative gingivitis is a clinical description of erythema and sloughing, usually a manifestation of lichen planus or a vesiculobullous disease, and is not acutely painful in this way.
• C. Granulomatosis with polyangiitis produces the strawberry gingivitis of granular red hyperplastic tissue, with sinus and renal involvement — rare and quite different.
• D. Ordinary plaque-induced gingivitis is not painful and does not destroy the papillae or produce this odour.

Note: Pain, interdental necrosis and bleeding are the three defining features. Loss of attachment distinguishes necrotising periodontitis from necrotising gingivitis.