Why do toenails thicken and curl?

Toenails can thicken and curl due to various factors, including fungal infections, aging, and underlying health conditions such as psoriasis or circulatory issues. Fungal infections often cause the nail to become discolored, brittle, and thickened. Additionally, improper footwear and repeated trauma to the toes can contribute to nail deformities. Maintaining foot hygiene and seeking medical advice for persistent changes can help manage these issues.