Affects both sexes, all races, and skin phototypes.
More common in women and patients with skin of color.
Incidence increases with age: less than 50% in the fourth decade, 50-80% after 40 years, over 90% in the ninth decade.
Uncommon in children and teens.
Familial cases are common.
Causes:
Multifactorial: aging, chronic sun exposure, genetic factors, and possibly trauma or autoimmune factors.
Abnormal keratinocyte phagocytosis leading to reduced melanin transfer.
Clinical Features:
Smooth pale or white macules, 2-5mm in diameter.
Commonly on the forearms, shins, and V of the chest.
Asymptomatic and usually multiple.
Morphological Variants:
Hypopigmented macules on sun-damaged skin.
Solitary white stellate sclerotic macule.
Small hypopigmented macules with a scalloped margin and hyperkeratotic surface.
Diagnostics:
More visible on darker skin.
Wood lamp examination highlights pigment loss.
Dermoscopy shows well-defined white areas, absent pigment network.
Complications:
Benign but of cosmetic concern, especially noticeable in darker skin tones.
Diagnosis:
Primarily clinical.
Skin biopsy to exclude other conditions; shows specific histological features like flat thin epidermis, decreased melanin, and normal/reduced melanocyte activity.
