Muehrcke’s lines

Muehrcke’s lines are two parallel white lines of pallor in the nail bed that are seen in patients with chronic hypoalbuminemia or low serum albumin ¹. Muehrcke’s lines are double white band parallel to the lunula ² that spans the entire nail bed. Applying the pressure on distal digits results in fading of these lines ². During the nail growth, they remain fixed and do not migrate distally ³. Muehrcke’s lines are usually narrow pairs of whitish, nonpalpable, transverse bands on the fingernails (it is uncommon for them to appear on the thumbnails) ⁴. Muehrcke’s lines are related to changes in the vascular bed rather than the nail itself, hence they do not move with nail growth ⁵. Muehrcke’s lines may fade with digital compression and when serum albumin levels increase ⁶. Muehrcke’s lines differ from Beau lines, which are palpable, and Mees lines also called leukonychia striata, which do not disappear on blanching ⁷ and Mees lines are expected to move along the nail growth ⁶.

Muehrcke’s lines can be associated with different clinical and pathological conditions and mostly will resolve after drug discontinuation or dietary support.

Figure 1. Muehrcke’s lines of the fingernails

Footnotes: A 46-year-old woman with metastatic sarcoma who had been treated with five cycles of doxorubicin, ifosfamide, and mesna chemotherapy presented with two symmetrical, horizontal white lines on all of her fingernails but not on her toenails. A diagnosis of Muehrcke’s lines was made. Muehrcke’s lines are the two smooth white bands that run parallel to the lunula across the width of the nail. The lines are nonpalpable and, unlike Beau’s lines, do not indent the nail itself. Normal-appearing pink nail-bed tissue is seen between the two white lines, and thumb involvement is rare. Muehrcke’s lines are a nonspecific finding that may be associated with periods of metabolic stress, which transiently impairs the ability of the body (and particularly of the liver) to synthesize proteins. Although the use of chemotherapy is one potential cause of Muehrcke’s lines, as illustrated in this patient, so are infections and trauma. Three months after presenting with Muehrcke’s lines, the patient died from progressive metastatic disease.

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Figure 2. Mees’ lines

Footnote:Mees’ lines in high altitude mountaineering. A 27-year-old man presented with Mees’ lines across his fingernails, across both hands. Mees’ lines were non-blanchable and the nails had no apparent depression. His toes were not affected. He was a never smoker, took no medications and had no relevant medical history. Six weeks previously, he had participated in a high-altitude mountaineering expedition in the Pakistani Karakorum range to a mountain called Spantik, the summit of which was at 7031 m.

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Muehrcke’s nails causes

Muehrcke’s lines are a nonspecific finding that may be associated with periods of metabolic stress, which transiently impairs the ability of the body (and particularly of the liver) to synthesize proteins and hypoalbuminemia, such as those secondary to infections, severe malnutrition, chronic diseases (e.g. liver diseases, renal insufficiency, or pellagra) and chemotherapy drugs (most frequently doxorubicin and cyclophosphamide) ¹⁰. Muehrcke’s lines are very common in patients receiving chemotherapeutic agents ¹¹, most commonly after treatment with anthracycline, cyclophosphamide, and vincristine and usually occur 3‐4 weeks of the use of agent ¹². There is a case report on Muehrcke’s lines induced by transretinoic acid therapy, an analogue of vitamin A, in patients with acute promyelocytic leukemia ¹³. There has also been a case report of a 58‐year‐old woman with transverse leukonychia due to acitretin treatments for palmoplantar pustular psoriasis published in 2013 ¹⁴.

Muehrcke’s lines other causes not influenced by hypoalbuminemia have been proposed, such as Muehrcke’s lines induced by altitude in Mount Everest expeditions ¹⁵.

Muehrcke’s lines pathogenesis is not completely known but may be caused by compression on the vessels of nail bed by local edema ¹⁶. The probable pathogenesis in the setting of chemotherapy is alteration of nail plate attachment to the nail bed due to vascular abnormalities due to chemotherapy ¹⁷.

References

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