White spots on the nails (Leukonychia): Understanding the causes and how to treat them

The nail is a specialised keratinised skin appendage that is often overlooked, although nail disorders account for approximately 10% of all dermatological conditions. Leukonychia is a common chromatic alteration of the nail characterised by white spots on the nails. Leukonychia was initially classified by Unna in 1896 into three types: punctate leukonychia, striated leukonychia, and total leukonychia. Subsequently, a fourth type, partial leukonychia, was added by Parkes Weber in 1918. Leukonychia has been subdivided into true leukonychia (affecting the nail plate), pseudoleukonychia (affecting the nail bed), and apparent leukonychia (associated with onycholysis). True leukonychia includes total, sub-total, or partial forms, the latter of which may be diffuse, transverse (striated), distal, or punctate.

Leukonychia, or white nails, is generally not a cause for alarm, but it can sometimes indicate serious systemic disorders or congenital conditions. The white color may be due to abnormalities in the nail plate or nail bed. Leukonychia may also be associated with factors such as trauma, nutritional deficiencies, infectious diseases, medications, or even more severe conditions affecting the liver or kidneys. In most cases, leukonychia does not require specific treatment and resolves on its own over time. We nevertheless recommend consulting a healthcare professional to assess the situation.

Transverse leukonychia, also known as Mees’ lines, was first described by Mees in 1919 in association with arsenic poisoning. These lines can also result from various conditions such as trauma, nutritional deficiencies, systemic diseases, infectious diseases, and medications. Cases of transverse leukonychia linked to severe hypocalcemia have even been reported. The differential diagnosis includes congenital transverse leukonychia and pseudoleukonychia. The latter is primarily caused by edematous changes in the nail bed tissues, often in association with hypoalbuminemia (Terry’s nail and Muehrcke’s lines) or renal failure. White spots and transverse striations are attributed to repeated microtrauma to the nail matrix. Dermoscopy, although rarely described, may reveal one or more transverse white bands on the nail plate, with a normally smooth surface.

It is commonly believed that white spots on the nails result from a deficiency in zinc and calcium. However, leukonychia, characterised by white spots on the nails, is generally attributed to microtrauma to the nail matrix. It may also be associated with other causes such as trauma, nutritional deficiencies, systemic diseases, fungal infections, allergic reactions, or medication side effects. Although zinc or calcium deficiencies may contribute to nail health issues, no direct link has been established between leukonychia and these specific deficiencies, as demonstrated by scientific studies.

Leukonychia can sometimes be associated with anemia. Anemia is a condition characterised by a decrease in the number of red blood cells or a reduced concentration of hemoglobin in the blood, which can sometimes affect the colour of the nails. However, it is important to note that leukonychia has various potential causes, and its association with anemia is just one possibility among many. If you are concerned about the colour of your nails or other symptoms, it is recommended that you consult a healthcare professional for a thorough evaluation.

Treatment of acquired leukonychia aims to eliminate the underlying cause. In most cases of true punctate leukonychia, this involves gentle nail care: avoiding manipulating the cuticles, limiting the frequent use of irritating or allergenic nail care products (nail polish/remover, artificial nails, nail glue). Frequent application of a moisturiser may be beneficial. Trauma is also a common cause of true transverse and punctate leukonychia and should be avoided. In some cases, an analysis of gait or footwear may be necessary. In cases of pseudoleukonychia caused by fungi, antifungal therapy is often indicated. In all cases, a consultation with a healthcare professional is recommended to establish a personalised diagnosis.

Leukonychia manifests as white spots on the nails, typically caused by microtrauma to the nail matrix or other conditions such as trauma, nutritional deficiencies, or systemic diseases. In contrast, yellow nails, or xanthonychia, often result from discolouration associated with lymphedema, fungal infections, smoking, frequent use of nail polish, or underlying medical conditions such as respiratory problems. Both conditions can be indicators of underlying health issues, requiring a medical evaluation to determine the specific cause and appropriate treatment.

Article published on December 1, 2023