Onychodystrophy impacting some or all nails is commonly associated with alopecia areata, with a prevalence ranging from 7%-84%. If all fingernails are affected, it is commonly referred to as twenty-nail dystrophy. The most common nail abnormalities are pitting, longitudinal ridging, leukonychia, and trachyonychia, but other nail changes such as onycholysis, red spotted lunulae, and onychomadesis may also be seen.

Trachyonychia occurs more frequently in children than adults with alopecia areata,  approximately 12% of children with alopecia areata compared with 3% of adults with alopecia areata.

Individuals with more severe alopecia areata (eg, alopecia areata totalis, alopecia areata universalis) are more likely to have nail changes. Nail changes may precede, follow, or coincide with the onset of hair loss.