Lichen planus may involve a solitary nail or all twenty nails; the condition is called twenty-nail dystrophy. The nail changes in lichen planus involves: - darkening of the nail - onycholysis - pterygium - anonychia Reference: https://dermnetnz.org/topics/lichen-planus#:~:text=Lichen%20planus%20thins%20the%20nail,%2C%20completely%20disappear%20(anonychia). Image via: https://dermnetnz.org/topics/lichen-planus#:~:text=Lichen%20planus%20thins%20the%20nail,%2C%20completely%20disappear%20(anonychia).