3. A 25-year-old man presents with what he describes as a “fungal infection” of the fingernails that he’s had since birth. The nails are uniformly thickened and dystrophic, without significant discoloration. The patient’s palms and soles are hyperkeratotic, and the upper anterior legs are covered by a folliculocentric papular hyperkeratosis reminiscent of a coarse keratosis pilaris.
Diagnosis: Pachyonychia congenita (PC) is a rare condition that represents a mutation of keratin genes and is usually of autosomal dominant inheritance. First described by Muller in 1904, it was eventually categorized into one of two types: type I, MIM 167200, also known as Jadassohn-Lewandowsky, the most common type, and type II, MIM 167210, also known as Jackson-Lawler, with slightly different features. Today, a more common view is that no such divisions exist—only variations of PC that exhibit overlapping features.
For more information on this case, see “A fingernail "infection" present since birth.” Clin Rev. 2013;23(4):W6.