What are the small white lesions in the mouth of an adolescent, possibly indicative of a fungal infection such as oral thrush?

Oral Thrush (Oropharyngeal Candidiasis)

The small white lesions in an adolescent's mouth are most likely oropharyngeal candidiasis (oral thrush), characterized by painless, creamy white, plaque-like lesions that can be easily scraped off with a tongue depressor, distinguishing them from other white oral lesions like oral hairy leukoplakia. 1

Clinical Presentation

The classic appearance includes:

• Painless, creamy white, plaque-like lesions on the buccal mucosa, oropharyngeal mucosa, or tongue surface that can be easily scraped off 1
• Less commonly, erythematous patches without white plaques on the palate or tongue 1
• Angular cheilitis may occasionally be present 1

Diagnostic Approach

Diagnosis is primarily clinical based on the appearance of lesions and the key distinguishing feature: the ability to scrape off the superficial whitish plaques. 1

If laboratory confirmation is needed:

• Obtain a scraping for microscopic examination using potassium hydroxide (KOH) preparation to visualize yeast forms 1
• Culture can identify the specific Candida species, though this is rarely necessary for initial management 1

Important caveat: If the white lesions cannot be scraped off or if the patient fails to respond to antifungal therapy, consider alternative diagnoses including herpes simplex virus, cytomegalovirus, eosinophilic esophagitis, or lymphocytic esophagitis, which require endoscopy with biopsy for definitive diagnosis 2.

Risk Factors to Assess

While Candida organisms are normal oral commensals in 40-65% of healthy adults 3, oropharyngeal candidiasis typically indicates some degree of immune compromise:

• CD4+ count <200 cells/µL in HIV-infected patients 1
• Diabetes mellitus, use of broad-spectrum antibiotics, or corticosteroids 3, 4
• Advanced age, though this can occur in otherwise healthy adolescents 3

Critical point: In adolescents, consider HIV testing if no other predisposing factors are identified, though recurrent vulvovaginal candidiasis alone should not be considered a sentinel for HIV infection 1.

Treatment Recommendations

For initial episodes in adolescents, oral fluconazole is the drug of choice due to superior efficacy, convenience, and tolerability compared to topical therapy. 1

First-Line Treatment Options:

Preferred:

• Oral fluconazole (dose and duration based on severity) 1

Alternative topical therapies for initial episodes:

• Clotrimazole troches 1
• Nystatin suspension or pastilles 1
• Once-daily miconazole mucoadhesive tablets 1

Expected Response:

• Improvement in signs and symptoms should occur within 48-72 hours 1
• If symptoms persist beyond 7-14 days, this constitutes treatment failure and requires reassessment 1

Management of Treatment Failure

If lesions persist after 7-14 days of appropriate therapy:

• Consider itraconazole oral solution for 7-14 days, which is effective in approximately two-thirds of fluconazole-refractory cases 1
• Posaconazole oral solution is effective in 75% of azole-refractory cases 1
• IV amphotericin B for truly refractory disease 1

Key consideration: Treatment failure should prompt evaluation for underlying immunodeficiency, including HIV testing, as refractory candidiasis typically occurs in patients with CD4+ counts <50 cells/µL who have received multiple azole courses 1.

Common Pitfalls to Avoid

• Do not assume all white oral lesions are candidiasis—confirm by attempting to scrape off the plaques 1
• Do not routinely prescribe prophylactic antifungals after treatment, as this promotes drug resistance, causes drug interactions, and is not cost-effective given the low mortality of mucosal candidiasis 1
• Do not ignore treatment failure—persistent symptoms beyond 7-14 days warrant investigation for immunodeficiency or alternative diagnoses 1, 2
• Do not rely on culture alone for diagnosis in the absence of clinical findings, as Candida is a normal commensal organism 1, 3