What condition is characterized by beaded hair that is weak before each node and easily broken?

The condition characterized by beaded hair that is weak before each node and easily broken is monilethrix. This hereditary disorder affects the hair shaft, resulting in a fragile structure with characteristic nodes along the strands. The term "monilethrix" itself refers to the beaded appearance, where the hair exhibits a series of small, bead-like swellings. This condition leads to increased fragility, making the hair more susceptible to breakage.

In contrast, trichorrhexis involves the hair shaft being brittle and prone to splitting but does not present with the beaded pattern characteristic of monilethrix. Alopecia refers to hair loss and does not involve the structural abnormalities seen in the other conditions. Telogen effluvium is a type of hair loss due to temporary disruptions in the hair growth cycle, but again does not characterize the structural issues like those seen in monilethrix. Thus, monilethrix accurately describes the specific condition involving beaded hair with weakness before each node and easily breakable strands.