ND is an uncommon, stable hypomelanosis that is usually congenital. Various clinical forms of this condition have been described either as isolated or systematized lesions.
The terms ND and hypomelanosis of Ito are today best taken as synonym. However, cases of hypomelanosis of Ito without extracutaneous anomalies are so far often categorized in the literature as ND, whereas cases of ND associated with extracutaneous anomalies are usually categorized as examples of hypomelanosis of Ito.
Hypomelanosis of Ito is a rare genetic disorder characterised by:
Streaky, patchy, whorl-like, or linear hypopigmented macules occurring on any part of the body. Lesions first appear as small 0.5-1 cm hypopigmented or white macules that merge to form larger patches, these patches are asymmetrical.
The genetic alteration of melanocytes in the hypopigmented lesion is assumed to resulted in the development of multiple pigmented nevi. The alteration is cused by chromosomal mosaicism and sporadic mutations. It is not an inherited disorder as the chromosomal defect occurs after conception. The specific gene(s) involved has not been confirmed.
Nevus depigmentosus : It is a congenital, well defined, hypo pigmented patch present since birth. It can be treated by spot dermabrasion or ablation with Co2 laser followed by ultra thin skin grafting.