Beau Lines in Nails, What are Beau Lines?

We often take the smooth, shiny appearance of our nails for granted, not realizing that the condition of our nails can change at any moment. This change may occur gradually or suddenly, but in the case of Beau’s lines, this change often occurs so slowly that you fail to realize that your nails’ appearance has drastically changed for the worse. The condition can easily go unnoticed, especially when it occurs on your toenails.

What are Beau Lines?

Beau’s lines are a type of nail condition in which the growth of the nail is abruptly terminated for a length of time, which causes deep lines to appear horizontally across your nail. The causes of Beau’s lines are most commonly physical nail injuries or repeated forces pushing back against the nail (e.g., shoes that are too small), causing a brief halt in cell production, or it can even be triggered by repetitive picking at the nails or nail cuticles. Sometimes internal and external causes correlate with these nail abnormalities. In the case of Raynaud’s disease, a blood vessel disorder localized within your finger and toe tip extremities, extremely cold environments may trigger these horizontal ridges known as Beau’s lines to appear due to a lack of blood circulation (1).

Beau’s lines may also appear in comorbid conditions, in which eczema or psoriasis in the skin around the nail bed may induce the lines to appear due to the close biological connection between the skin and nail (1). In the case of hand-foot-and-mouth disease, nail matrix arrest was caused by infection by several viral strains or inflammation of the nail matrix (2). In some cases, these lines may be indicative of severe systemic disease or health disorders, which cause extreme stress on the body.

Periods of stress include bodily trauma in the case of shock due to low blood pressure levels, extremely low levels of calcium, elevated body temperatures or high fevers due to fever and infections, a severe deficiency in nutrition, and the resting periods following myocardial infarctions and chemotherapy treatment. High levels of inflammation in certain disorders, such as mumps, coronary thrombosis, and pulmonary infections, may also cause Beau’s lines to appear on all ten fingernails and impact nail growth overall (1).

Impact of Beau’s Lines on Nails

The trajectory of the disease is illustrated by the physical characteristics of the nail, in which steep, deep lines indicate a sudden onset and severe disorder, while a sloping, rounded edge reveals a gradual onset of the disease (1). These deep lines appear due to problems in the distal matrix and the proximal nail matrix, which affect all layers of nail cell production. The distal matrix affects the deeper layers of the nail, creating deep ridging while the proximal nail matrix affects the top layer of the nail, leading to pitting in conditions like psoriasis (1).

Continued growth of keratin leads to the development of these lines after the nail disruption period has grown out (1). If the lines appear repeatedly without a visible source of trauma, the cause may be a systemic or autoimmune disorder and in this case, you should consult with your primary physician to rule out any internal deficiencies or malfunctioning in your general organs. Afterwards, you may be directed to a dermatologist, who will be able pinpoint the exact cause if it is external and prescribe an ointment treatment for the Beau’s lines.

View more nail glossary terms at https://doctorsklineandgreen.com/glossary

References:1. Thomas, L. (2019). “Beau’s Lines”. News Medical Life Sciences. Retrieved from: https://www.news-medical.net/health/Beaue28099s-Lines.aspx

2. Shin, J. Y., Cho, B. K., & Park, H. J. (2014). “A clinical study of nail changes occurring secondary to hand-foot-mouth disease: onychomadesis and beau’s lines”. Annals of Dermatology 26(2), pp. 280-283, doi: 10.5021/ad.2014.26.2.280.

3. Photo from public domain – https://en.wikipedia.org/wiki/Beau%27s_lines#/media/File:Beau’s_line_on_left,_middle_fingernail.jpg