Twenty-nail dystrophy

Although the symptoms of twenty-nail dystrophy usually begin in childhood, adults can also be affected by this condition.^[1]  One article in the medical literature describes a woman who first showed symptoms of this condition at age 21.^[2]  Another article describes an individual who was 63 when he first developed symptoms in his fingernails, but his toenails were not affected.  He was diagnosed with tachyonychia, and twenty-nail dystrophy is thought to be a type of tachyonychia.^[3]

The exact cause of twenty-nail dystrophy is unknown.  Most cases occur by chance without any other symptoms.  In some cases, twenty-nail dystrophy has been diagnosed in individuals who also have another skin condition such as alopecia areata, eczema, or psoriasis; this has led some physicians to question whether the skin condition causes twenty-nail dystrophy in those individuals.^[3][4]  And in a few rare cases where several members of the same family have been affected by this condition, physicians suspect there may be a genetic cause.^[1]

There is a recognized association between hair loss and twenty-nail dystrophy, but it is not known if one condition causes the other.  Individuals with twenty-nail dystrophy often also have hair loss, though the extent of hair loss varies from mild to severe.  In severe cases of hair loss, the individual may have a condition called alopecia areata.^[4]