Final answer:
A condition affecting the nail due to injury, disease, or imbalance is typically referred to as a fungal infection, where the infected nail becomes yellow and brittle.
Step-by-step explanation:
A condition caused by injury to the nail or some disease or imbalance in the body is called a fungal infection. Fungal infections of the nail, also known as tinea unguium, can be caused by dermatophytes or Candida species. These infections result in nails that become yellow, brittle, and prone to breaking. This condition is relatively common, especially among adults. Cutaneous mycoses are fungal infections that affect the skin, hair, and nails without spreading to the underlying tissue. For nails, this condition is typically treated with antifungal medications.