Diseases of the nails

5  Non-tumorous skin diseases

5.16  Diseases of the nails

This chapter shows some nail diseases; nail mycosis see the chapter onychomycosis.


Examples of nail dystrophie:

Examples of nail discolorations:

5.16.1  Posttraumatic onycholysis


  • posttraumatic destruction of the nail

5.16.2  Psoriatic onycholysis

Clinical signs:

  • nails are affected in some psoriatic patients
  • nail changes (pits, oil spots, subungual hyperkeratosis)

5.16.3  Onychoschisis

5.16.4  Onychogryphosis

5.16.5  Onychophagia

Clinical signs:

  • habitual biting of the nails

5.16.6  Pterygium unguis

5.16.7  Unguis incarnatus

Clinical signs:

  • lateral nail folds on the toes, usually big toe
  • painful swelling
  • purulent discharge around the nail
  • caused bu imporper nail trimming or badly fitting shoes


The nail grows into the lateral nail fold. The ingrowth leads to inflammatin and formation of granulation tissue.


Unguis incarnatus:
Unguis incarnatus, HE 20x (5050)

5.16.8  Foveolae unguis

5.16.9  Leuconychia striata

Clinical signs:

Whitish discoloration of the nail.

5.16.10  Melanonychia striata

Clinical signs:

Brown discoloration of the nail.

5.16.11  Syndrome Laugier Hunziker

Clinical signs:

  • melanonychia striata
  • pigmentations of the lips, buccal mucosa and sometimes gingiva or tongue
  • pigmented macules up to 10 mm in size
  • no other anomalies
  • rare


Prominent pigmentation of the basal layer and melanophages in the papillary dermis. Basal membrane is intact.

5.16.12  Twenty nail dystrophy


  • unknown
  • lichen ruber (?)
  • eczema (?)

Clinical signs:

  • rough nails
  • discoloration
  • fragmentation

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