Porokeratosis of the Nail Unit: Case Series and Review

Abstract Background: The lesions of porokeratosis (PK) lead to skin atrophy and scarring as long as they spread centrifugally. PK affecting the nail unit is seldom described. Objective: The aim was to revise the previously reported cases of ungual PK and to present 3 new cases. Methods: A PubMed search was performed with the keywords “nail” and “porokeratosis.” Previously reported cases as well as 3 new cases are depicted in tables. Results: Only 11 cases of ungual PK were found; 3 new cases have been added. All patients presented with typical lesions of PK (Mibelli, isolated, segmental, or ostial eccrine types) that happened to affect nails due to nail matrix or nail bed compromise, resulting in mild to severe nail scarring, including irreversible anonychia. The present 3 case series contrast with the previous single case reports. Conclusions: PK affecting the nails is exceedingly rare. Changes in nails affected by PK are irreversible, since, as on the skin, this is a chronic scarring process.