- Common finding in elderly individuals
- Brown, macules located on sun-exposed areas ("liver spots“-on the back of the hands, and face)
- Increased number of melanocytes which produce excessive melanin.
- Not precancerous
- No treatment is required
- Focal overproduction of melanin with normal number of melanocytes with increase in melasosomes.
- Freckles are sharply demarcated light brown-ginger macules of upto 5mm in diameter due to over production of melanin.
- Most prominent in sun exposed sites, and multiply and become darker with sun exposure
- Common in blacks
- Autoimmune destruction of melanocytes
- Causes extensive areas of skin depigmentation
- Often associated with other autoimmune conditions like diabetes, thyroid and adrenal disorders and pernicious anemia.
- Segmental vitiligo- is restricted to one part of the body, but necessarily a dermatome.
- Generalised vitiligo- is often symmetrical and involves the hands, wrists, knees, neck and area around the body orifices.
- The hair of the scalp and beard may also depigment.
- The patches of depigmentation are sharply defined.
- Protecting the patches from excessive sun exposure with clothing and sunscreen- helps in reducing episodes of burning and potentially of skin cancer.
- Potent topical corticosteroids
- Phototherapy with PUVA
It occurs when the melanocytes are unable to synthsize melanin ( either by absence of tyrosinase activity or inability of cells to take up tyrosine)
Macular, hyperpigmented lesions on the forehead and cheeks
Female predominance; exacerbated (melanocytes produce more melanin) by:
a. Oral contraceptives (OCP)
b. Pregnancy ("pregnancy mask")
Application of hydroquinone (bleaching agent) to skin