Pachyonychia congenita with only nail involvement.

Dear Editor, A 10-year-old boy presented with progressive thickening of the nails over the previous 5 years. He did not have any other cutaneous and/or systemic symptoms. He was born to healthy non-consanguineous parents following an uneventful pregnancy. Upon examination, he was found to have symmetrical involvement of the finger and toenails with marked hard thickening of the distal portion of the nail plate resulting in uplifting and tenting (Fig. 1). The palms and soles, oral cavity and scalp were normal. Potassium hydroxide examination of nails did not reveal any fungi. Systemic examination did not reveal any abnormalities. Pachyonychia congenita is a rare, autosomallydominant disorder characterized by symmetrical hard thickening of the nails with marked subungual hyperkeratosis, palmoplantar keratoderma with thick callosities, and oral leukokeratosis. 1 Various other abnormalities such as hyperkeratotic follicular papules of the extremities, keratosis pilaris, blister formation of feet and palms, hair abnormalities, and hyperhidrosis of palms and soles have also been reported. 2