A patient presents with a brown-to-black, hair-like coating on the dorsal surface of the tongue, sparing the tip and lateral borders. There is no pain, but the patient reports halitosis and a tickling sensation. Which of the following best describes the method used to diagnose this condition?

Hairy tongue (lingua villosa) results from elongation and hypertrophy of the filiform papillae due to decreased oral stimulation, poor hygiene, tobacco use, or antibiotic therapy. The papillae can grow up to 18 mm and trap chromogenic bacteria producing the characteristic brown-to-black discoloration. Diagnosis is CLINICAL — based on the appearance of elongated, hair-like papillae on the dorsum of the tongue and a compatible history. A biopsy is rarely necessary and only indicated when the lesion does not respond to conservative management or the diagnosis is uncertain. Key differentials: oral hairy leukoplakia (EBV-associated, white, lateral tongue, cannot be wiped off); pseudomembranous candidiasis (white plaques that CAN be wiped off, wipeable). Treatment: gentle debridement, improved oral hygiene, and removal of causative factors (antibiotics, smoking, coffee).