Muehrcke's nails or Muehrcke's lines (
apparent leukonychia striata) are changes in the
fingernail
A nail is a claw-like plate found at the tip of the fingers and toes on most primates. Nails correspond to the claws found in other animals. Fingernails and toenails are made of a tough protective protein called alpha-keratin, which is a polymer ...
that may be a
sign of an underlying medical condition. The term refers to a set of one or more pale transverse bands extending all the way across the nail, parallel to the
lunula. In contrast to
Beau's lines, they are not grooved (no 3-dimensional deformity), and in contrast to
Mees' lines, the thumb is usually not involved.
Muehrcke's lines are a strong indicator of
hypoalbuminemia
Hypoalbuminemia (or hypoalbuminaemia) is a medical sign in which the level of albumin in the blood is low. This can be due to decreased production in the liver, increased loss in the gastrointestinal tract or kidneys, increased use in the body, or ...
, which can result from a variety of different causes.
The lines are actually in the vascular bed underneath the nail plate. As such, they do not move with nail growth, and disappear when pressure is applied to the nail (blanching the underlying nail bed): this distinguishes them from "true leukonychia striata" such as Mees' lines.
As in
Terry's
Terry's is a British chocolate and confectionery maker, formerly based in York, England, until 2005, and re-established in 2019 as Terry's Chocolate Co and based in London. The company was founded in 1767. The company's headquarters and fact ...
and
half-and-half nails, the pattern is thought to be formed by bands of localized edema exerting pressure on the surrounding capillaries.
Physiology
The appearance of Muehrcke's lines is associated
specifically with marked
hypoalbuminemia
Hypoalbuminemia (or hypoalbuminaemia) is a medical sign in which the level of albumin in the blood is low. This can be due to decreased production in the liver, increased loss in the gastrointestinal tract or kidneys, increased use in the body, or ...
(serum albumin ≤ 2.2 g/dL) indicating decreased protein synthesis, which may occur during periods of metabolic stress (e.g. systemic infection, trauma,
AIDS,
chemotherapy
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs ( chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemothe ...
), or in
hypoalbuminemic states such as the
nephrotic syndrome or
dietary protein deficiency. They are also seen in patients with end-stage kidney disease on
hemodialysis
Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...
,
Hodgkin's disease,
pellagra
Pellagra is a disease caused by a lack of the vitamin niacin (vitamin B3). Symptoms include inflamed skin, diarrhea, dementia, and sores in the mouth. Areas of the skin exposed to either sunlight or friction are typically affected first. Over t ...
, and
sickle cell anaemia
Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red b ...
.
The lines remain visible as long as protein intake is inadequate or synthesis is impaired, and they should disappear upon return to normal function.
In extreme conditions, Muehrcke's lines may also arise from physical changes in peripheral circulation: one case study reported appearance of the lines in a healthy subject following ascent to 8,848 meters (29,029 ft) on
Mount Everest
Mount Everest (; Tibetic languages, Tibetan: ''Chomolungma'' ; ) is List of highest mountains on Earth, Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border ru ...
.
History
Muehrcke's lines were described by American physician
Robert C. Muehrcke (1921–2003) in 1956. In a study published in
BMJ, he examined patients with known chronic hypoalbuminemia and healthy volunteers, finding that the appearance of multiple transverse white lines was a highly specific marker for low serum albumin (no subject with the sign had SA over 2.2 g/dL), was associated with severity of the underlying condition, and disappeared upon successful treatment (corticosteroids in nephrotic syndrome) or direct infusion of
HSA.
See also
*
Mees' lines – a similar appearance, except the lines are in the nail and move as the nail grows
*
Half and half nails
*
Terry's nails
*
List of cutaneous conditions
References
Bibliography
*
*James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. .
*
Muehrcke's Lines of the Fingernailson WebMD
{{Eponymous medical signs for integumentary system
Conditions of the skin appendages
Medical signs