What condition might a person with thickened nails be experiencing?

A person with thickened nails may be experiencing onychomycosis, which is a fungal infection of the nail. This condition often leads to the nail becoming thicker, discolored, and possibly separating from the nail bed. Onychomycosis is particularly noted for its tendency to affect the toenails more than fingernails, and it can be quite persistent if not treated properly.

Thickening of the nails is primarily associated with fungal infections because the fungi invade the keratin in the nails, leading to abnormal growth patterns. In this case, distinguishing onychomycosis from other conditions is important, as the specific appearance and progression of the nail's changes can confirm the diagnosis.

Other conditions, such as brittle nails and psoriasis, can lead to various nail changes, but they do not solely account for the thickening associated with a fungal infection. Brittle nails typically involve splitting or breaking rather than thickening, while psoriasis may cause pitting or ridging but typically does not lead to a thickened nail plate unless there is an underlying fungal infection as well.