A patient on chlorite tetracycline presents with numerous non-painful white lesions in the oral cavity. What is the most likely diagnosis?

The presence of numerous non-painful white lesions in the oral cavity of a patient using chlorite tetracycline strongly suggests candidiasis, particularly when taking into account the impact of antibiotics on normal flora. Chlorite tetracycline is an antibiotic that can disrupt the balance of microorganisms in the oral cavity, leading to an overgrowth of Candida species, the yeast responsible for oral thrush.

Candidiasis typically presents as white lesions that can be scraped off, revealing a red and possibly bleeding surface beneath. The lesions are usually non-painful, aligning with the patient's presentation.

In contrast, oral herpes would typically present with painful vesicular lesions rather than non-painful ones. Angular cheilitis tends to manifest at the corners of the mouth and is often accompanied by cracks or sores, not widespread white lesions throughout the oral cavity. Similarly, leukoplakia involves thick, white patches on the oral mucosa, but this condition is often associated with irritation or precancerous changes and may not present in the same widespread manner, nor is it specifically linked to antibiotic use.

Hence, considering the symptoms and the context of antibiotic therapy, candidiasis is the most likely diagnosis.