NEW ORLEANS – .
“The mainstay of treatment is irritant avoidance and moisturization,” Shari R. Lipner, MD, PhD, associate professor of clinical dermatology and director of the nail division at Weill Cornell Medicine, New York, said at the annual meeting of the American Academy of Dermatology. “This works well if patients are religious about doing it.”
Dr. Lipner
Dr. Shari R. Lipner
Brittle nail syndrome affects about 20% of adults, she said, and is more common in females, particularly those older than age 50. Most cases are idiopathic, but some are secondary to dermatologic diseases including nail psoriasis and nail lichen planus, and systemic diseases such as hyperthyroidism and hypothyroidism. They are more common in patients in certain occupations such as carpentry. “The pathogenesis is poorly understood but is thought to be due to weakened intercellular keratinocyte bridges, decreased cholesterol sulphate in the nail plate, and reduced water content in the nail plate,” Dr. Lipner said.
Key clinical findings include onychoschizia (peeling of the nail plate), onychorrhexis (an increase in the longitudinal ridges and furrows, sometimes leading to splitting), and superficial granulation of keratin. Treatment involves general measures. “You want to treat the underlying cause and recommend that the patient avoid water and irritant exposure,” she said. Her general instructions for affected patients are to wear latex gloves for wet work and cotton gloves for dry work, avoid triclosan-based hand sanitizers, avoid nail cosmetics, minimize nail trauma, and foster moisturization.“It’s important to give these instructions verbally and in written form,” she said. “In our practice, we designed a QR code that links to our patient handout.”
According to Dr. Lipner, the promotion of vitamins and supplements such as biotin, vitamin D, amino acids, and chromium for treating brittle nail syndrome is rampant on the Internet and on social media, but no rigorously designed clinical trials have shown efficacy for any of them. “Very few people are deficient in biotin, except for those with inherited enzyme deficiencies,” and most people “can get all the biotin they need from a regular diet,” she said.
The initial rationale for using biotin for nails comes from the veterinary literature, she continued. In the 1940s, chickens with biotin deficiency developed fissures in their feet and parrot-like beaks. In the 1970s, pigs with biotin deficiency developed friable hooves, which was corrected with biotin supplementation. “By the 1980s it was standard practice to supplement the feet of pigs with biotin,” she said.
In a human trial from 1989, German researchers enrolled 71 patients with brittle nail syndrome who took oral biotin, 2.5 mg daily. Of the 45 patients evaluated, 41 (91%) showed improvement in firmness and hardness of the fingernails over the course of 5.5 months, but there was no good control group, Dr. Lipner said. In a follow-up study, the same German researchers used scanning electron microscopy to evaluate 22 patients with brittle nails who took oral biotin 2.5 mg daily and compared them with 10 patients with normal nails who did not take biotin. They found a 25% increase in nail plate thickness in the biotin group and onychoschizia resolved in 50% of patients who received biotin. “But again, there was no good control group,” Dr. Lipner said.
In a third study on the topic, researchers surveyed 46 patients who presented with onychorrhexis and/or onychoschizia on clinical exam and took 2.5 mg of biotin daily. Of the 35 survey respondents, 63% subjectively reported improvement in their nails at a mean of 2 months. “This is where we are today: There have been studies of only 80 patients that were done 25 years ago,” Dr. Lipner said. “That’s all of our evidence for biotin for the treatment of brittle nail syndrome.”