What condition is characterized by deep horizontal ridges on a nail?

Beau's lines are characterized by deep horizontal ridges that can form on the nails. These lines occur due to temporary interruptions in nail growth, which can happen as a result of various physiological stresses, including systemic illness, trauma, surgery, or severe nutritional deficiencies. The presence of Beau's lines indicates that there has been a period where the nail matrix activity was affected, leading to the formation of these distinctive grooves. Understanding this condition is important in dermatology as it can provide insights into a patient’s overall health and any underlying medical issues they may be experiencing.

Other conditions, such as lichen planus, can affect the nails as well, but they usually present with different symptoms rather than the distinct horizontal ridges of Beau's lines. Nail pterygium involves the skin growing over the nail plate, and subungual hematoma is characterized by blood pooling under the nail, which does not produce the horizontal ridges seen in Beau's lines. Thus, the identification of Beau's lines is crucial for recognizing specific health conditions related to nail growth.