The condition of your toenails may change throughout your life. Brittle toenails can develop as you get older, or they may be an indicator of an underlying medical problem. See your doctor for an accurate diagnosis of the cause of your brittle toenails.
Toenails may become more brittle as a part of the body's natural aging process. To minimize damage, keep your toenails trimmed and moisturized, avoid picking at them and wearing constrictive shoes, and avoid nail polish. Nail polish itself can cause chemical damage and brittle toenails.
Toenails, like skin, can become brittle when they dry out. This most often occurs with repeated exposure to moisture. The condition is exacerbated by low atmospheric humidity. Brittle toenails that are simply dried out are usually easily treated with soaking and applying lotion.
Brittle toenails are a typical symptom of a fungal nail infection called onychomycosis. Other symptoms include discoloration or dulling of the nail's natural shine, thickening of the nail and changes to the shape of the nail. Treatment is usually a course of oral prescription antifungal medication such as terbinafine or itraconazole. In other instances, a topical antifungal medication, such as ciclopirox, is prescribed.
An underactive or overactive thyroid sometimes causes brittle toenails. Although both types of thyroid dysfunctions can cause nail problems, an underactive thyroid is the more likely culprit for brittle toenails. Other symptoms include pale or yellowed skin, cold and dry skin, puffy eyelids and hands or weakened hair.
Although an uncommon cause, certain nutritional deficiencies can lead to brittle toenails. In particular, a deficiency of iron or biotin, one of the B-complex vitamins, might be to blame. In some cases, there may be an underlying health condition that affects the absorption of nutrients contributing to your deficiency.