<s>[INST] Hello doctor, I have an eight month old baby. There is a white patch on her back. It has been there without any changes since 3 months. Is this vitiligo? [/INST] Hi. I have seen the white patches of your baby in the attached pictures (attachment removed to protect patient identity). This is not vitiligo, because 1. Vitiligo will be depigmented and not hypopigmented as in your case. 2. Vitiligo is very rare in infancy. 3. Vitiligo is almost always progressive before coming to a stable phase (in most cases). So, it can be nevus achromicus or nevus depigmentosus. To differentiate between the two conditions, clinical examination and Woods light examination is required. Revert back to a dermatologist online for further follow up --> </s>