Linear and whorled nevoid hypermelanosis

Alternate names

LWNH; Nevoid hypermelanosis, linear and whorled; Linear and whorled hypermelanosis; Zosteriform lentiginous nevus; Zebra-like hyperpigmentation; Zosteriform hyperpigmentation; Reticulate hyperpigmentation of Iijima

Definition

Linear and whorled nevoid hypermelanosis (LWNH) is a rare benign condition affecting skin pigment occurring in newborns or early infancy.

Epidemiology

• It is unknown how many people have linear and whorled nevoid hypermelanosis.
• Most of the information on this condition comes from cases described in the medical literature.

Cause

• The exact cause of linear and whorled nevoid hypermelanosis (LWNH) is not known.
• It is thought to result from a genetic change called mosaicism, that occurs early in the development of an embryo.
• People with mosaicism have two sets of cells each with a different genetic makeup.
• Several chromosome abnormalities have been reported in affected individuals.
• People with LWNH who have an underlying chromosome abnormality are more likely to have symptoms in addition to those that affect the skin.

Inheritance

• Linear and whorled nevoid hypermelanosis (LWNH) generally occurs by chance in people with no family history (sporadically).
• A few rare cases of LWHN in more than one member of a family have been described.

Signs and symptoms

Symptoms may include:

• Swirling streaks of darkened (hyperpigmented) skin
• Developmental delay
• Asymmetric growth
• Cardiovascular defects
• The dark skin streaks appear in early infancy and are generally found on the trunk and limbs.
• The face, palms of the hand, and soles of the feet are not generally affected.
• The hyperpigmentation may get progress for a few years, and then become stable.
• In some people, the darkened skin streaks fade with time.
• Most people with LWNH have no medical problems related to their condition.

Diagnosis

It is diagnosed based on the symptoms.

Treatment

• There is no specific treatment for linear and whorled nevoid hypermelanosis (LWNH).
• It is considered a mild condition and no medical treatment may be necessary.
• Methods to lighten the skin including chemical peels and laser treatments may be helpful.
• Due to the possible association with chromosome abnormalities and other conditions, people with LWNH should be evaluated for developmental delays, growth delays, skeletal abnormalities, and congenital heart defects.
• One specialist who might be involved in the care of someone with LWNH is a dermatologist.