White Coating on Tongue: Causes and Treatment
The most common cause of white coating on the tongue is oral thrush (candidiasis), which requires antifungal treatment, while benign tongue coating related to poor oral hygiene responds to mechanical cleaning with tongue brushing.
Primary Causes
Oral Thrush (Candidiasis)
- Candida albicans is the most common pathogen responsible for white coating, accounting for the majority of oral thrush cases 1
- Non-albicans species (C. glabrata, C. dubliniensis, C. krusei) can also cause white coating, particularly in fluconazole-resistant cases 1
- The white plaques of candidiasis can be scraped off, revealing a bright red underlying surface 2
- Diagnosis is confirmed by scraping and microscopic examination with KOH preparation 2
Benign Tongue Coating
- Grayish-white deposits on the tongue dorsum are the main cause of intra-oral halitosis and represent accumulation of microorganisms 3
- Poor oral hygiene is the strongest determinant factor for the presence of tongue coating 4
- Smoking, denture use, periodontal disease, and dietary habits also contribute to coating formation 4
HPV-Related Lesions
- Verruca vulgaris (HPV 2 and 4) presents as well-circumscribed growths with prominent hyperkeratosis, giving a white pebbly surface 5
- Oral squamous papillomas can appear white depending on the degree of keratinization 5
- These lesions occur via autoinoculation from fingers to mouth 5
Risk Factors for Oral Thrush
High-Risk Populations
- Immunosuppression is a major risk factor, particularly HIV infection with CD4+ counts <200 cells/μL 1
- Corticosteroid use, including inhaled steroids, increases risk 1
- Head and neck radiation therapy predisposes to fungal overgrowth 1
- Diabetes and immunocompromised states increase susceptibility 5
Medication-Related
- Antibiotic treatment can disrupt oral microflora balance and cause white coating 6
- Topical corticosteroid use in the mouth can lead to candidiasis as the most common side effect 7
Treatment Approach
For Oral Thrush (Candidiasis)
- Antifungal therapy is required for candidal infections 2
- Nystatin oral suspension or miconazole oral gel are first-line topical treatments 7
- Fluconazole is used for systemic therapy, though resistance can develop with repeated exposure 1
- Effective antiretroviral therapy is the best prophylaxis against recurrent oral thrush in HIV-infected patients 1
For Benign Tongue Coating
- Tongue brushing on a regular basis, particularly aiming at removing the coating on the dorsum of the tongue, has been found effective in reducing oral malodour 8
- Improve oral hygiene practices as the primary intervention 4
- Address contributing factors: smoking cessation, denture hygiene, periodontal treatment 4
For HPV-Related White Lesions
- Surgical excision is the recommended treatment for oral verruca vulgaris, squamous papilloma, and condyloma acuminatum 5
- Biopsy may be necessary to exclude dysplasia, particularly in immunosuppressed individuals 5
Supportive Care Measures
General Oral Hygiene
- Clean the mouth daily with warm saline mouthwashes 5
- Use antiseptic oral rinses (1.5% hydrogen peroxide or 0.2% chlorhexidine) twice daily to reduce bacterial colonization 5
- Apply white soft paraffin ointment to lips if crusting is present 5
When to Suspect Alternative Diagnoses
- Black tongue coating may indicate gastrointestinal issues and responds to treatment of underlying conditions 6
- Persistent white lesions despite antifungal treatment warrant biopsy to exclude malignancy 5
- Thick white coating with systemic symptoms (fever, rash) requires evaluation for conditions like scarlet fever or Kawasaki disease 2
Common Pitfalls
- Do not use topical antibiotics for fungal infections, as they are ineffective and may promote further fungal overgrowth 5
- Routine fluconazole prophylaxis is not recommended due to concerns about drug resistance development 1
- Monitor patients on topical corticosteroids for development of oral candidiasis 7
- In immunocompromised patients, consider systemic antifungals in addition to topical therapy 5