Final answer:
Onychitis is the inflammation of nails, often resulting from fungal infections. The nails are composed mainly of keratin.
Step-by-step explanation:
Onychitis refers to the inflammation of nails. When considering options that describe types of inflammation, it's important to look at the prefix for clues. 'Onycho-' refers to the nails, and thus, onychitis is correctly identified as inflammation of the nails, which can often be the result of fungal infections. Onychitis is commonly caused by fungal infections, such as dermatophytic skin infections or infections of fingernails and toenails. These infections can result in symptoms such as yellowing, brittleness, and breaking of the nails. Fungal infections of the nail, such as tinea unguium, can be caused by dermatophytes or Candida spp., leading to symptoms like yellowing and brittleness of the nails. Nails themselves are composed mainly of a protein called keratin, which is also a primary component of hair and skin.