Nail changes
Synonyms and keywords: Nail abnormality; nail disorders; nail signs

# Overview
Nail diseases are distinct from diseases of the skin. Although nails are a skin appendage, they have their own signs and symptoms which may relate to other medical conditions. Nail conditions that show signs of infection or inflammation require medical assistance and cannot be treated at a beauty parlor. Deformity or disease of the nails may be referred to as onychosis.
There are many examples of how nail changes can play a role in helping to diagnose certain conditions. For example, short, small nail beds, and redness are associated with various heart conditions.

# Classification Scheme
Some images shown below are courtesy of Professor Peter Anderson DVM PhD and published with permission  PEIR, University of Alabama at Birmingham, Department of Pathology
Acral lentiginous melanomaDoctor definition: Acral lentiginous melanoma is a kind of skin melanoma, and it is also known as subungual melanoma.Patient definition: Acral lentiginous melanoma is a kind of skin cancer, and it is also know as a skin cancer that manifests under the nail.
AcrocyanosisDoctor definition: Acrocyanosis is a persistent blue or cyanotic discoloration of the digits. Patient definition: Acrocyanosis is a blue discoloration (cyanosis) of the fingers and the fingernails.
AtherosclerosisDoctor definition: Atherosclerosis is a disease affecting arterial blood vessels and it can cause changes to the nail beds. Patient definition: Atherosclerosis is a disease affecting arterial blood vessels and it can cause changes to the nail beds.
Beau's linesDoctor definition: Beau's lines are deep grooved lines that run from side to side on the fingernail.Patient definition: Beau's lines are deep grooved lines that run from side to side on the fingernail.
Bowen's diseaseDoctor definition: Bowen's disease is a sunlight induced skin disease considered either as an early stage or intraepidermal form of squamous cell carcinoma.Patient definition: Bowen's disease is a sunlight induced skin disease considered an early stage for of skin cancer.
Brittle nailsDoctor definition: Brittle nails is a condition where the nails are fragile and break frequently.Patient definition: Brittle nails is a condition where the nails are fragile and break frequently.
Digital clubbingDoctor definition: Digital clubbing is a deformity of the fingers and fingernails that is associated with a number of diseases, mostly of the heart and lungs.Patient definition: Digital clubbing is a deformity of the fingers and fingernails that is associated with a number of diseases, mostly of the heart and lungs.
Half and half nailsDoctor definition: Half and half nails refer to a change in the appearance of the nails due to internal diseases and nutritional deficits.Patient definition Half and half nails refer to a change in the appearance of the nails due to internal diseases and nutritional deficits.
Herpes simplexDoctor definition: Herpes simplex is a viral disease caused by Herpes simplex viruses.Patient definition: Herpes simplex is a viral disease caused by Herpes simplex viruses.
IschemiaDoctor definition: Ischemia is a restriction in blood supply, generally due to factors in the blood vessels, which result in damage or dysfunction of tissue.Patient definition: Ischemia is a restriction in blood supply, generally due to factors in the blood vessels, which result in damage or dysfunction of tissue.
KoilonychiaDoctor definition: Koilonychia refers to nails (usually of the hand) which have lost their convexity, becoming flat or even concave in shape.Patient defintion: Koilonychia literally means spoon nails. It is when your nails become flat or sunken in.
LeukonychiaDoctor definition: Leukonychia  is a medical term for white discoloration appearing on nails. Patient defintion: Leukonychia is a medical term for white discoloration appearing on nails.
Lichen planus nail changes Doctor definition: Lichen planus is an inflammatory disease that affects the skin and the oral mucosa.Patient definition: Lichen planus is an inflammatory disease that affects the skin and the mouth.
Mee's linesDoctor definition: Mees' lines are lines of discoloration across the nails of the fingers and toes after an episode of poisoning with arsenic or thallium or other heavy metals. Patient definition: Mees' lines are lines of discoloration across the nails of the fingers and toes after an episode of poisoning with arsenic or thallium or other heavy metals.
MelanonychiaDoctor definition: Melanonychia is a black or brown pigmentation of the normal nail plate that can present as horizontal or longitudinal bands.Patient definition: Melanonychia is a black or brown pigmentation of the normal nail plate that can present as horizontal or longitudinal bands.
Muehrcke's linesDoctor definition: Muehrcke's lines are white lines across the nail associated with hypoalbuminemia.Patient definition: Muehrcke's lines are white lines across the nail associated with low levels of the most abundant blood protein (albumin).
OnychiaDoctor definition: Onychia is an inflammation of the matrix of the nail with formation of pus and shedding of the nail.Patient definition: Onychia is an inflammation of the surrounding tissue (matrix) of the nail with formation of pus and shedding of the nail.
OnychocryptosisDoctor definition: Onychocryptosis is a painful condition in which the nail grows or cuts into one or both sides of the nail bed.Patient defintion: Onychocryptosis is a painful condition in which the nail grows or cuts into one or both sides of the nail bed.
OnychodystrophyDoctor definition: Onychodystrophy is a deformation of the nails that can result from cancer chemotherapy which includes bleomycin, hydroxyurea, or 5-fluorouracil. Patient definition: Onychodystrophy is a deformation of the nails that can result from certain cancer drugs (bleomycin, hydroxyurea, or 5-fluorouracil).
OnychogryphosisDoctor definition: Onychogryposis, also called "ram's-horn nail", is a thickening and increase in curvature of the nail.Patient definition: Onychogryposis, also called "ram's-horn nail", is a thickening and increase in curvature of the nail.
OnycholysisDoctor definition: Onycholysis is a loosening of the exposed portion of the nail from the nail bed, usually beginning at the free edge and continuing to the lunula. Patient definition: Onycholysis is a loosening of the exposed portion of the nail from the nail bed, usually beginning at the free edge and continuing to the crescent-shaped whitish area of the bed of a fingernail or toenail.
OnychomadesisDoctor definition: Onychomadesis is a periodic idiopathic shedding of the nails beginning at its proximal end.Patient definition: Onychomadesis is a periodic, spontaneous shedding of the nails beginning at the end closer to the finger.
OnychomycosisDoctor definition: Onychomycosis is a fungal infection of the nails. Patient definition: Onychomycosis is a fungal infection of the nails.
OnychophosisDoctor definition: Onychophosis is a localized or diffuse hyperkeratotic tissue that develops on the lateral or proximal nailfolds, within the space between the nailfolds and the nail plate.Patient definition: Onychophosis is a localized or diffuse excess of the nail proteins that develops on the side of the nail closer to the finger. This forms specifically in the space between the nail folds and nail plate.
OnychoptosisDoctor definition: Onychoptosis is the periodic shedding of the nails.Patient definition: Onychoptosis is the periodic shedding of the nails.
PachyonychiaDoctor definition: Pachyonychia is an autosomal dominant skin disorder.Patient definition: Pachyonychia is a skin disorder that is expressed when the specific gene is present.
Paronychia Doctor defintion: Paronychia is an often tender bacterial or fungal infection where the nail and skin meet at the side or the base of a finger or toenail. Patient definition: Paronychia is an often tender infection where the nail and skin meet at the side or the base of a finger or toenail.
Pitted nails Doctor definition: Pitted nails are pinpoint depressions in the nails.Patient definition: Pitted nails are pinpoint depressions in the nails.
Platonychia Doctor definition: Platonychia is characterized by an abnormally flat and broad nail. Patient definition: Platonychia is characterized by an abnormally flat and broad nail.
Psoriatic nails Doctor definition: Psoriatic nails is a common nail disease associated with people who have psoriasis. Patient definition: Psoriatic nails is a common nail disease associated with people who have a scaly skin rash (psoriasis).
SclerodermaDoctor definition: Scleroderma is a rare, chronic disease characterized by  excessive deposits of collagen in the skin or other organs.Patient definition: Scleroderma is a rare, long lasting disease characterized by excessive deposits of a structural protein in the skin or other organs.
Skin cancerDoctor definition: Skin cancer is a malignant growth on the skin which can have many causes.Patient definition: Skin cancer is invasive, spreading cancer on the skin which can have many causes.
Splinter hemorrhage Doctor defintion: Splinter hemorrhages are tiny lines that run vertically under the nails.Patient definition: Splinter hemorrhages are tiny lines that run vertically under the nails.
Subungual hematomaDoctor definition: A subungal hematoma is a hematoma underneath a toenail or fingernail which often results from a traumatic injury such as slamming a finger in a door.Patient definition: A subungal hematoma is a collection of blood underneath a toenail or fingernail which often results from a traumatic injury such as slamming a finger in a door.
Terry's nailsDoctor definition: Terry's nails is a physical finding in which fingernails and/or toenails appear white with a characteristic "ground glass" appearance, with no lunula.Patient definition: Terry's nails is a physical finding in which fingernails and/or toenails appear white with a characteristic "ground glass" appearance, with no white crescent shaped area at the bottom of the nail.
TraumaDoctor definition: Trauma refers to a physical injury.Patient definition: Trauma refers to a physical injury.
Tuberous sclerosisDoctor definition: Tuberous sclerosis is a rare, multi-system genetic disease that causes benign tumors to grow in the brain and on other vital organs such as the kidneys, heart, eyes, lungs, and skin. Patient definition: Tuberous sclerosis is a rare, multi-system genetic disease that causes benign tumors to grow in the brain and on other vital organs such as the kidneys, heart, eyes, lungs, and skin.
WartDoctor definition: A wart is generally a small, rough tumor, typically on hands and feet, that can resemble a cauliflower or a solid blister.Patient definition: A wart is generally a small, rough tumor, typically on hands and feet, that can resemble a cauliflower or a solid blister.
Yellow nail syndromeDoctor definition: Yellow nail syndrome is characterized by yellow nails that lack a cuticle, grow slowly, and are loose or detached (onycholysis). Patient definition: Yellow nail syndrome is characterized by yellow nails that lack a cuticle, grow slowly, and are loose or detached (onycholysis).