Mees' lines are white, transverse (side-to-side) bands on fingernails or toenails, signaling a serious underlying systemic illness, poisoning (like arsenic, thallium), severe infection, kidney disease, chemotherapy, or heart failure, caused by temporary disruption of nail growth at the matrix. These smooth, non-blanching lines move outward as the nail grows, indicating the time of the stress event, and resolve once the cause is removed.
Mees' lines are defined as transverse white bands in the nail plate that are often caused by trauma to the nail matrix or systemic diseases. These lines can indicate conditions such as arsenic poisoning and may present with smoother borders and a more homogeneous appearance when associated with systemic disease.
Transverse white nail lines, or Mees lines, have been associated with acute systemic stress, such as from acute renal failure, heart failure, ulcerative colitis, breast cancer, infection (measles, tuberculosis), and systemic lupus erythematosus, and with exposure to toxic metals such as thallium.
Drug-induced true leukonychia (Mees' lines) appears as one or several parallel transverse white bands affecting all nails at the same level and moving distally with nail growth5. Beau's lines are typical signs of acute toxicity to the nail matrix with transient arrest in nail plate production.
Mees lines may be confused with Muehrcke lines (i.e., apparent leukonychia), which are paired white lines caused by vascular congestion in the nail bed. Muehrcke lines are easily distinguished from Mees lines because Muehrcke lines fade with digital compression and do not migrate with the growth of the nail.
Are Mees' lines serious? Mees' lines are often a symptom of an underlying health problem. You should talk to a healthcare provider if you notice these bands in your nails.
Like other types of melanoma, subungual melanoma develops in melanocytes, the pigment cells that give skin its color. Unlike most types of skin cancer, subungual melanoma isn't related to sun exposure. Nail melanoma often shows up as a narrow brown or black streak or band on the nail.
Discolored nails that look yellow or greenish. Thick, dry cuticles that are ragged and tear easily. Redness around the nail (called periungual erythema) Fungal infections — people with autoimmune disorders like Sjögren's are at higher risk for infections.
Monitoring Changes in Nails
Be especially cautious with changes on your thumb, big toe, or cuticle areas, as subungual melanoma most often starts there. Regular self-examinations can help in early detection, making it crucial to monitor any unusual changes in these areas.
Liver disease can cause distinct nail changes, most notably Terry's nails, where nails appear mostly white with a small pink/reddish band at the tip, lacking the normal half-moon (lunula), resembling "ground glass". Other signs include yellowing, thickening, clubbing (nails curve downwards), leukonychia (white spots/bands), and nail separation (onycholysis). These changes reflect issues with blood flow, low albumin, or connective tissue in the nail bed, often seen with cirrhosis.
Nail infections with yeasts or fungi are common among people with diabetes – usually affecting toenails. 4 White/yellow/greenish discolouration and thickening at the end of the nail spreads gradually to involve the whole nail which may be thick and brittle.
Beau's lines may be caused by:
Heart failure nails often show nail clubbing, where fingertips enlarge and nails curve downward like an upside-down spoon due to poor oxygen flow, feeling soft and warm, but can also present as blueish tints (cyanosis) or splinter hemorrhages (tiny red lines under nails) from heart infections (endocarditis). Other signs can include Terry's nails (mostly white with a pink tip) or Mees lines (horizontal white bands). These changes signal serious underlying issues, requiring prompt medical evaluation.
2 Nail changes in vitamin B12 deficiency present as hyperpigmentation of nails like bluish discoloration of nails, blue-black pigmentation with dark longitudinal streaks, and longitudinal and reticulate darkened streaks.
A magnesium deficiency can result in weak, flaky nails that are prone to breakage.
The 5 key signs of melanoma, often remembered by the ABCDEs, are Asymmetry (uneven halves), Border irregularity (jagged edges), uneven Color (multiple shades), Diameter larger than a pencil eraser (about 6mm), and Evolving (changing in size, shape, color, or symptoms like itching/bleeding). Also watch for a sore that doesn't heal, new dark streaks under nails, or unusual sensations like itching or pain in a mole.
The survival rate is high when subungual melanoma is detected early. Survival rates are about 95% when it's caught at an early stage and treated quickly. If subungual melanoma is diagnosed later and cancer has spread, the survival rate can be as low as 15%.
Equipment used for Nail Biopsy
For numbing your skin during the biopsy, a local anesthetic called 1% lidocaine solution is often used. This prevents you from feeling pain during the procedure.
Lupus can cause various fingernail changes including ridges, splitting, discoloration, and separation from the nail bed, which may appear differently depending on skin tone.
Three key signs of Sjögren's syndrome are dry eyes, dry mouth, and chronic fatigue, stemming from the autoimmune system attacking moisture-producing glands, leading to gritty, burning eyes, difficulty swallowing or speaking, and persistent tiredness, often accompanied by joint pain and swollen glands.
Curved nails with swollen fingertip
A swollen fingertip, curved nail, and thickening skin above a nail are often signs of thyroid disease.
However, it can develop in any nails of the fingers and toes. Nail unit melanoma tends to be diagnosed equally among the sexes, and is most common in people between the ages of 50-70. However, anyone can develop this disease at any age.