Thickened toenails are a common but often overlooked health concern that can signal underlying issues requiring attention. They result from factors such as fungal infections, injuries, or medical conditions like diabetes and psoriasis.

Dr. Abigail Waldman, a dermatologist at Brigham and Women’s Hospital, highlights that feet provide an ideal environment for fungi due to their dampness, often leading to infections that start on the skin and spread to toenails.

Conditions such as onychomycosis, where a new nail grows beneath an infected one, and onychauxis, which causes curling and yellowing, are frequent culprits. Injuries or immune-related conditions can also cause thickened nails.

Symptoms often include discoloration, brittleness, debris under the nails, and foul odors. Left untreated, these issues can lead to complications like tissue damage, nail loss, or infections that spread to surrounding areas, potentially causing severe health problems like cellulitis or even sepsis.