Brittle nails may dry out, crumble, split, develop jagged edges, become discolored and otherwise appear abnormal. There are a variety of possible causes of brittle toenails, and they range from the relatively harmless to serious health concerns. Treatment options depend on the underlying cause, so you should seek diagnosis of your condition from a doctor or dermatologist.
Drying Out
Toenails, like skin, sometimes become brittle when they dry out. This most often occurs with repeated exposure to moisture, according to the American Osteopathic College of Dermatology, or AOCD. The condition is exacerbated by low atmospheric humidity. Brittle toenails that are simply dried out are usually readily treatable by soaking the toes for about five minutes and then applying a moisturizer. Look for products containing lanolin or alpha-hydroxy acids.
Fungal Infection
Brittle toenails are a typical symptom of a fungal nail infection known as 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, according to MayoClinc.com. Treatment is usually a course of oral prescription antifungal medication such as terbinafine or itraconazole. In other instances, a topical antifungal prescription, such as ciclopirox, is the treatment.
Nutritional Deficiency
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, according to dermatologist Dr. Audrey Kunin's DermaDoctor website. Treatment typically entails increasing intake of biotin or iron-rich foods and possibly supplementation under a doctor's supervision. In some cases, your doctor might need to determine whether underlying health conditions that affect the absorption of nutrients contribute to your deficiency.
Thyroid Disorders
An underactive or overactive thyroid sometimes causes brittle nails as a symptom. This may be due to hypothyroidism or hyperthyroidism, but a number of health conditions affect the performance of the thyroid, and treatments vary. 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, according to the New Zealand Dermatological Society.
Aging
Sometimes, toenails become more brittle as a part of the body's natural aging process, according to the University of Maryland Medical Center. 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, according to the American Osteopathic College of Dermatology.
