Pachyonychia L60.2

Congenital or acquired thickening and hardening of the nail plate (gr.: pachys= thick), possibly with enlargement and deformation(onychogrypose) as a result of increased and disturbed nail growth.

As a single term for a nail condition the term is not very common. In connection with the congenital "Pachyonychia congenita" it is the eponym. S. a. Scleronychia.

The symptom Pachyonychia or Onychauxis occurs reactively as an isolated symptom in the following diseases or influences on the skin:

• as a consequence of trauma
• in case of frostbite
• by strong pressure effects on the nail, e.g. by too tight shoes
• in acromegaly
• in Darier's disease
• in psoriasis
• in pityriasis rubra pilaris

Furthermore, the symptom is observed hereditarily associatively in syndromes e.g. in pachyonychia congenita or in combination with diffuse alopecia (Nikoo A 2012).

It has also been described as a non-syndromic autosomal recessive nail dysplasia (syn: Claw-Shaped Nails, NDNC10) due to a mutation in the FZD6 gene (gene locus 8q22.3).

1. Nikoo A (2012) Pachyonychia congenita-associated alopecia. Case Rep Pathol 2012:850658.