DermNet NZ

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Twenty-nail dystrophy

What is twenty-nail dystrophy?

Twenty-nail dystrophy is also known as ‘trachyonychia’. It could be said that twenty-nail dystrophy is widespread trachyonychia involving all 20 nails. The condition is characterised by longitudinal ridging (alternating elevation and depression), pitting, loss of lustre, and roughening (similar to sandpaper) of the nail surface.

What are the signs and symptoms?

Twenty-nail dystrophy most commonly occurs in childhood. In one study the condition was most evident in young males in the 10-20 year old age group (52%). Slight nail abnormalities may be evident at birth with the condition slowly progressing over the years to cause changes in the texture of fingernails and toenails. Typical signs and symptoms include:

Trachyonychia Trachyonychia Trachyonychia
Twenty nail dystrophy

What causes twenty-nail dystrophy?

The cause of twenty-nail dystrophy is unknown but in some cases it appears to be associated with other skin conditions such as lichen planus, eczema, psoriasis and alopecia areata. In some cases an autosomal dominant pattern of inheritance has been found; in one report twenty-nail dystrophy occurred in 4 males in 3 successive generations. Other cases of twenty-nail dystrophy are of unknown origin and begin gradually in early childhood. These cases tend to be self-limiting and may resolve slowly with age.

What treatment is available?

There is no specific treatment for twenty-nail dystrophy. It is a very difficult condition to treat and often results are unsatisfactory. Some treatments that have been tried include:

Related information


On DermNet NZ:

Other websites:

Books about skin diseases:

See the DermNet NZ bookstore

Author: Vanessa Ngan, staff writer

DermNet NZ does not provide an online consultation service.
If you have any concerns with your skin or its treatment, see a dermatologist for advice.