Reasons that can affect the appearance of toenails:

1. The most common reason is a fungus. A fungus is an organism that lives and thrives in warm, moist areas. This makes our shoes the perfect breeding ground for these pesky little organisms. Toenail fungus can affect people of every age but, it most commonly affects older people. Treating toenail fungus is best if caught early, so even if you notice the slightest change to your nails, don’t hesitate to see your local podiatrist. They may take a sample of your toenail to send away to a lab to confirm the diagnosis before prescribing you a topical antifungal or oral medication. 

2. Toe Trauma/Injury – dropping something on your toe or stubbing it can result in permanent damage to the nail. 

3. Systemic skin conditions such as eczema or psoriasis.

4. Peripheral vascular disease or poor blood circulation to the extremities is a problem that affects many people and can also cause toenails to become dry and brittle.

5. Rarer than common reasons, include yellow nail syndrome and even endocarditis has been linked with splinter hemorrhages aka small, red lines seen in the nail.