Final answer:
The most likely diagnosis for the described symptoms is herpetic gingivostomatitis, although oral candidiasis, aphthous ulcers, or acute necrotizing ulcerative gingivitis could also be considered depending on additional clinical findings.
Step-by-step explanation:
The presentation of multiple white lesions on the tongue, sore gums, a fever of 101, and the age of the patient suggests a few possible diagnoses. The most likely diagnosis for a 20-year-old patient with these symptoms is herpetic gingivostomatitis caused by the Herpes Simplex Virus Type 1 (HSV-1). This condition leads to ulcers across the mucous membranes inside the mouth and is typically self-limiting. However, if the lesions are cottage cheese-like, an oral candidiasis (thrush) infection could also be considered, particularly in immunocompromised individuals.
Other differential diagnoses could include aphthous ulcers (canker sores), which are non-contagious and usually heal on their own, or acute necrotizing ulcerative gingivitis (trench mouth), which is severe and characterized by gum erosion and intense pain, often requiring antibiotics. Given the systemic symptoms of fever and the localized oral findings, herpetic gingivostomatitis is more probable, and antiviral medications like acyclovir may be used for treatment.
Final diagnosis should be confirmed through clinical examination and possibly cultures or biopsies, as visual cues alone may not distinguish between all potential causes of white lesions in the mouth.