:Onychoschizia
{{See also|Onychorrhexis}}
{{Short description|Splitting of the free-edged tip of the nail}}
Onychoschizia, also known as nail splitting and brittle nails, is a splitting of the free-edged tip of the nail.{{cite book |last1=Sloan |first1=Brett |editor1-last=Waldman |editor1-first=Reid A. |editor2-last=Grant-Kels |editor2-first=Jane M. |title=Dermatology for the Primary Care Provider |date=2022 |publisher=Elsevier |location=Philadelphia |isbn=978-0-323-71236-1 |pages=277–278 |chapter-url=https://books.google.com/books?id=IfwqEAAAQBAJ&dq=Onychoschizia&pg=PA277 |language=en |chapter=16. Multiple nail: nail splitting}} There is also often a longitudinal split in addition to the separation of keratin layers.{{cite book |last1=James |first1=William D. |last2=Elston |first2=Dirk |last3=Treat |first3=James R. |last4=Rosenbach |first4=Misha A. |last5=Neuhaus |first5=Isaac |title=Andrews' Diseases of the Skin: Clinical Dermatology |date=2020 |publisher=Elsevier |location=Edinburgh |isbn=978-0-323-54753-6 |page=785 |edition=13th |chapter-url=https://books.google.com/books?id=UEaEDwAAQBAJ&dq=Diseases&pg=PA785 |language=en |chapter=33. Diseases of the skin appendages }}
Cause
Frequent hand-washing is the usual cause, but it is also part of normal ageing.{{cite book|last=Johnstone |first=Ronald B.|title=Weedon's Skin Pathology Essentials |url=https://books.google.com/books?id=NTE_DAAAQBAJ|year=2017|publisher=Elsevier |isbn=978-0-7020-6830-0|edition=2nd|page=31|chapter=2. Diagnostic clues and "need-to-know" items}} Manicures, nail polish and remover, nail biting, and repeated trauma such as typing, can contribute to nail splitting. Dehydration likely plays a role. Nutritional deficiencies that can result in nail splitting include iron, selenium, and zinc. Some skin diseases such as psoriasis and lichen planus may feature such nails.
Diagnosis
Diagnosis is by its appearance, but sometimes blood tests are required to look for iron deficiency, thyroid problems, and kidney problems.
Treatment
Epidemiology
Other animals
It also occurs in hooved animals such as horses.{{cite journal |last1=Colombo |first1=Victor E. |last2=Gerber |first2=Françoise |last3=Bronhofer |first3=Max |last4=Floersheim |first4=George L. |title=Treatment of brittle fingernails and onychoschizia with biotin: Scanning electron microscopy |journal=Journal of the American Academy of Dermatology |date=December 1990 |volume=23 |issue=6 |pages=1127–1132 |doi=10.1016/0190-9622(90)70345-i |pmid=2273113 }}
See also
References
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