Lindsay’s nails in a patient followed up for antiphospholipid syndrome

A 55-year-old Caucasian woman was referred by a dermatologist to the immunology outpatient clinic due to Raynaud’s syndrome (capillaroscopic findings consistent with the primary Raynaud's syndrome) and skin lesions with the livedo reticularis type located on the extremities. Additionally, matte white discoloration of the proximal portions of the nail plates of the hands was observed, with a sharp line of demarcation to the brown-colored distal parts (figs. 1, 2). The patient’s history revealed one miscarriage before 10 weeks of pregnancy. The diagnostic work-up found no evidence of internal organ damage, except for thickening of the mitral valve leaflets seen on echocardiogram and no indications of thromboembolic incidents. Serological tests showed antinuclear antibodies with a granular fluorescence pattern at a titer of 1 : 160 and antibodies with a Golgi fluorescence pattern at a titer of 1 : 640. Also, the presence of IgM anticardiolipin antibodies at a significant titer was detected twice (over 12 weeks apart), and IgM antibodies against β2-glycoprotein were identified once. The patient did not meet the Sydney criteria or the 2023 ACR/EULAR criteria to diagnose antiphospholipid syndrome. Consequently, a diagnosis of undifferentiated connective tissue disease with features of antiphospholipid syndrome was established. Treatment with hydroxychloroquine and acetylsalicylic acid was initiated. The patient continues to be under dermatological and immunological follow-up.
Lindsay’s nails (LN; also known as ‘half and half nails’) are a condition described in 1962 by physicians William B. Bean and James Clifton in two patients with azotemia, and in 1967 by Philip G. Lindsay in 25 patients (after reviewing a group of 1,500 individuals) with chronic kidney disease [1, 2]. Lindsay’s nails is a condition characterized by a clearly visible transverse division of the nail plate into two distinctly colored portions. The proximal part appears matte white, resembling a crystal, while the distal part is darker in color, ranging from pink to red-brown, covering between 20% and 60% of the nail surface [1–4]. LN can affect either a single nail apparatus (NA) of one extremity or involve all the NAs of the patient’s upper (more commonly) and/or lower extremities. Lindsay’s nails is a type of apparent leukonychia: the translucency of the nail plate is preserved (unlike in true leukonychia and pseudoleukonychia), and the white color fades on pressure [1, 2].
The pathophysiology of the condition is not fully understood, but it is hypothesized that the white coloration in the proximal portion of the nail is a consequence of ischemia induced by the thickening or compression (due to pathological deposition of connective tissue) of the blood vessels in the subpapillary plexus. Consequently, blood flow is restricted, and nail bed swelling occurs. In the red-pink variant of LN, the color of the distal portion of the NA bed is attributed to the accumulation of melanin stimulated by melanocyte-stimulating hormone (MSH). In the classic (i.e. kidney disease-related) form of LN, it is hypothesized that azotemia not only stimulates melanocytes for melanin production but also slows down nail growth, leading increased pigment accumulation [1, 2, 4].
Lindsay’s nails are linked to various conditions, especially metabolic and autoimmune diseases. However, the disorder has also been reported as a consequence of external factors, including medications, and observed in individuals with no underlying health issues (table 1). Antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of antiphospholipid antibodies in the patient’s blood, contributing to an elevated susceptibility to blood clot formation. APS is linked to various changes within the nail apparatus, including splinter hemorrhages, cyanotic nails, and clubbed fingers [5]. No clear association of LN with antiphospholipid syndrome has been reported to date. However, a literature review suggests that Kumar et al. may have documented the link between both conditions [6]. The authors presented the case of a female patient with black discolorations within the NA, accompanied by finger pain, secondary to lupus erythematosus and APS. Analysis of the photographs of the patient’s hands, with lesions evident on all fingers, is consistent with a diagnosis of LN.
It is important to highlight that APS can lead to renal damage, causing a reduction in glomerular filtration rate and secondary azotemia. Given that LN have been most frequently reported in patients with kidney diseases (6.9–20% of cases), the manifestation of such changes in the NA may serve as an indication for particularly vigilant monitoring of kidney function in the described patient [6].

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