Background: Gingivitis in children is commonly associated with dental biofilm and is generally reversible. However, severe gingival inflammation accompanied by spontaneous bleeding, fever, oral ulceration, and poor nutritional status warrants evaluation for underlying viral, necrotizing, hematologic, or nutritional disorders. Case Presentation: A 10-year-old girl presented with gingival swelling of one-week duration, preceded by fever and associated with spontaneous bleeding during tooth brushing and sleep. Pinpoint ulcerations were observed on the labial mucosa and lips. Intraoral examination revealed generalized reddish-pink, swollen, and hyperemic gingiva with loss of stippling, rolled gingival margins, bulbous papillae, and bleeding on probing. The patient's height and weight were 161 cm and 29 kg, respectively, corresponding to a calculated body mass index of approximately 11.2 kg/m². In view of the clinical presentation and nutritional status, physician assessment was advised. Panoramic examination did not reveal generalized alveolar bone loss. Based on the clinical findings, a diagnosis of acute generalized gingivitis was established. Complete hand scaling, oral-hygiene instruction, chlorhexidine mouth rinse, vitamin C supplementation, multivitamin supplementation, and physician referral were advised. Follow-up photographs obtained at 10 and 25 days demonstrated marked clinical resolution of the gingival inflammation.Conclusion: Severe generalized gingival inflammation in a child, particularly when accompanied by spontaneous bleeding, fever, oral ulceration, or poor nutritional status, requires prompt local biofilm control and consideration of systemic and nutritional modifiers. Clinical improvement following scaling and supplementation should not, in isolation, be interpreted as confirmation of a specific vitamin deficiency.