What causes white patches on the face?

White patches on the face may be caused by several factors, mainly including: 1. Vitiligo: An autoimmune disease in which the body's immune system mistakenly attacks melanocytes, leading to white patches on the skin. This may be related to genetic factors, immune system dysfunction, and environmental factors (such as sun exposure, infections, trauma), among others. 2. Candidiasis (white fungal infection): A type of fungal infection that may invade skin tissues under certain conditions, causing an inflammatory response and subsequently forming white patches. 3. Psoriasis: Associated with genetic factors, environmental factors, and immune system abnormalities, it can lead to excessive proliferation of keratinocytes, forming erythematous scaly plaques, sometimes covered with white scales. 4. Vitamin B12 deficiency: Vitamin B12 plays an important role in neuronal development and maintenance. Deficiency may affect neurotransmitter synthesis and metabolism, interfere with neural signal transmission, and trigger symptoms such as white patches. 5. Diabetes: A state of high blood sugar may lead to insufficient nutrient supply to epidermal cells, affecting their growth cycle, and consequently cause microvascular skin lesions, resulting in changes in skin color.