How can I differentiate between oral candidiasis and other causes of oral lesions in a patient?

To differentiate oral candidiasis from other causes of oral lesions, a thorough clinical assessment is essential, focusing on characteristic features, risk factors, and response to treatment. Oral candidiasis typically presents as white, creamy plaques on the mucosal surfaces that can often be wiped away, revealing erythematous or bleeding areas underneath. In contrast, other oral lesions such as leukoplakia, erythroplakia, or malignancies present as persistent white or red patches that do not scrape off and may be associated with ulceration or induration ¹.

Risk factors for oral candidiasis include immunosuppression (e.g., HIV infection), diabetes, use of corticosteroids or antibiotics, ill-fitting dentures, and nutritional deficiencies. Identifying these factors supports the diagnosis of candidiasis over other lesions ¹ (Farah et al., 2010). The presence of recurrent or extensive lesions, or lesions unresponsive to antifungal treatment, should raise suspicion for alternative diagnoses or malignancy, warranting specialist referral and possible biopsy ¹.

Clinically, oral candidiasis may manifest in different forms such as pseudomembranous (white plaques), erythematous (red patches), or chronic plaque-like candidiasis. The latter can mimic leukoplakia and carries a risk of malignancy if unresponsive to treatment, thus requiring biopsy ¹. Other oral lesions, including leukoplakia and erythroplakia, are typically persistent, non-removable patches and are considered premalignant, necessitating urgent referral for assessment ².

Diagnostic confirmation can be supported by microbiological swabs or cytology, especially if the diagnosis is uncertain or if the lesion does not respond to initial antifungal therapy ¹. In immunocompromised patients, such as those with HIV, oral candidiasis is common and may be the first sign of immune deficiency, highlighting the importance of considering systemic causes (Grbic and Lamster, 1997).

In summary, differentiation relies on clinical appearance (removable white plaques vs. persistent patches), risk factor assessment, response to antifungal treatment, and when in doubt, specialist referral and biopsy. This approach aligns with UK clinical guidelines and is supported by literature emphasizing the importance of recognizing underlying causes and the potential for malignancy in non-responsive lesions ¹ (Farah et al., 2010; Krishnan, 2012).