Trachyonychia (derived from the Greek trakos for rough) is an acquired condition of rough nails and is characterized by ridging, longitudinal grooves, opaque discoloration and roughness, and an increased tendency for nail breakage (see also Chapter 22: Diseases and Abnormalities of Nails).

Trachyonychia can occur in one or multiple nails. When all 20 nails are involved the condition is called 20-nail dystrophy, although this term is often used when the typical changes are present even in only a few nails.

In children, trachyonychia most commonly occurs as an isolated condition, but it may be seen in association with skin diseases such as atopic dermatitis, alopecia areata, or psoriasis.

Clinical presentation varies from mild disease presenting as thin brittle nails with excessive longitudinal ridging and pits to severe disease manifesting as thick, opaque, sandpaper-like nails (Figs. 9.15 and 9.16).

The cuticle is usually hyperkeratotic and ragged.

Koilonychia (spoon-shaped nails) may be present.

It may involve one, several, or all digits.

Made on clinical grounds and ruling out of causative conditions.