Pigmented transverse nasal band: A distinct presentation.

Pigmented transverse nasal band (PTNB) is an interesting morphological entity mainly of cosmetic concern. It is believed to be related to a defect in the development of the nasal cartilages and bones from childhood to adolescence. Some patients may have genetic predisposition. It is asymptomatic in nature and may be associated with certain dermatological conditions such as seborrheic diathesis, dermatosis papulosa nigra, ichthyosis, atopic dermatitis, acne vulgaris, psoriasis, and seborrheic melanosis.