Onychomycosis, or fungal infection of the nail, most often affects the toenails. Infected nails usually have a thick, yellow appearance and can become coarse and brittle (see Figure 4). When ...

Most of the time, psoriasis is the first symptom of psoriatic arthritis. It causes silvery-white skin lesions called plaques, which may appear on your scalp, elbows, knees, and lower back. Eventually, ...