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What Do Your Brittle Nails Say About Your Health?

One of the more common nail findings I see during routine examination of the skin is splitting of the nails, known as onychoschizia. The splitting occurs at the free edge of the nail, separating the nail edge into layers. Why would I as a dermatologist care about the appearance of nails? Nails are an extension of the skin. And just like our skin can give clues about our internal health, so too can the nails. For example, onychoschizia could be a sign of a vitamin deficiency or an internal disorder. Although these are uncommon causes for brittle nails, it's something that I as an board-certified dermatologist and internist don't like to miss.

I hope the following tips help provide more information about how dermatologists can help with more than just skin. Happy #DermTipTuesday!


Causes of Brittle Nails

External Causes

Clue: finger nails are brittle, but the toe nails are strong


  • Too much moisture

Common culprit(s): household chores, i.e. dish washing

Clue: nails are soft and brittle

Tip: wear cotton lined rubber gloves to minimize chemical and water exposures

  • Too little moisture

Common culprit(s): climates low in humidity, acetone containing nail polish remover, dehydration

Clue: nails are dry and brittle

Tip: moisturize the hands regularly throughout the day and the cuticles nightly; use oily polish removers; drink plenty of water to remain hydrated throughout the day

Internal Causes

Clue: finger nails and toe nails brittle


  • Vitamin deficiency

Biotin is a common and effective recommendation for brittle nails. In fact, biotin supplementation has been proven to help more with the appearance of nails than hair.

Iron deficiency is another common cause of brittle nails. Women who are of child-bearing age are especially prone to iron deficiency, presenting with brittle nails more often than men. If you suspect you could have iron deficiency, it is best to have the appropriate labs drawn with supplementation monitored by a physician.

  • Disorders

Internal disorders will present with more signs and symptoms than just brittle nails. But with the proper history, complete physical exam, and labs, these disorders can be properly diagnosed.

Endocrine examples: diabetes mellitus, hyperthyroidism (over active thyroid), hypothyroidism (under active thyroid), postmenopausal phase, pregnancy

Hematologic example: anemia

Infectious examples: syphilis, tuberculosis

Metabolic examples: anorexia nervosa, bulimia nervosa, malnutrition

Rheumatologic examples: rheumatoid arthritis, sarcoidosis, systemic lupus erythematosus

  • Drugs

Oral retinoids, like isotretinoin for the treatment of acne, and chemotherapeutic agents are examples of drugs that are commonly known to cause brittle nails.


As a reminder, always seek care from a board-certified dermatologist to be certain of the cause of any dermatologic condition.

Gequelim GC, et. al.: Perception of brittle nails in dermatologic patients. An Bras Dermatol 2013; 88: pp. 1022.

Van de Kerkoff P.C., Pasch M.C., Scher R.K., et al: Brittle nail syndrome: a pathogenesis-based approach with a proposed grading system. J Am Acad Dermatol 2005; 53: pp. 644-651

Gupta M.A., Gupta A.K., and Haberman H.F.: Dermatologic signs in anorexia nervosa and bulimia nervosa. Arch Dermatol 1987; 123: pp. 1386-1390

Michel C., Cribier B., Sibilia J., et al: Nail abnormalities in rheumatoid arthritis. Br J Dermatol 1997; 137: pp. 958-962

Patel K.B., and Sharma O.P.: Nails in sarcoidosis: response to treatment. Arch Dermatol 1983; 119: pp. 277-278

Trueb R.M.: Involvement of scalp and nails in lupus erythematosus. Lupus 2010; 19: pp. 1078-1086

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