Discussion:
Glabrous skin of palm and the papillary ridges is characterized by absence of hair follicles and sebaceous glands. Hairy skin complications are frequent in VKHD. Integumentary changes like alopecia, poliosis and vitiligo are late complications in this disease. The presence of vellus hairs on palm similar to cheeks have been demonstrated.7 Melanocytes are found in meninges and inner ear in addition to eye, skin and hairs. The pathogenesis of VKHD though not completely understood, involves auto antigens, the melanocyte differentiation proteins, like tyrosinase (TYR), tyrosinase-related peptide (TRP)-1, TRP-2.8,9 These proteins are the enzymes involved in the synthesis of melanin and are present specifically in melanocytes.10 Additional auto antigens, like KU-MEL-1 and lens epithelium-derived growth factor have a role through an IgG-mediated mechanism.9 The genetic predisposition involves certain genetic or epigenetic factors resulting in immune dysregulations.11 The growth of hairs on palmer surface of distal phalanx of the thumb may be the result of auto antigens along with immune dysregulations.