The most common cause of those funny ridges down the middle of thumbnails is surprising – and it’s reversible. The ridging, also called habit-tic deformity, is caused by flicking the nail and adjacent cuticle.
This practice is a tension-releasing habit that many people have. When done often, the cuticle callouses and thickens, altering nail growth under the cuticle and a ridged nail slowly emerges.
An Easy Fix
The fix is to control the flicking and hydrate the cuticle and nail. A smooth nail will emerge over time. Learn more on this by visiting my new advice page: Why Do My Thumbnails Ridge Down the Center?
If you know someone troubled by this type of nail ridging, share the info with them – they will be thrilled! In all my decades of dermatology practice, I’ve seen this condition repeatedly but can’t remember one patient who made the connection on their own. The habit of nail flicking can be subconscious!