Hyperpigmentation

There is wide variation in the pattern of normal pigmentation as a result of heredity and exposure to the sun. Darkening of the skin may be due to an increase in the normal pigment melanin or to the deposition of bile salts in liver disease, iron salts (haemochromatosis), drugs, or metallic salts from ingestion. In agyria ingested silver salts are deposited in the skin. Causes of hyperpigmentation include the following factors.

Hormonal

An increase in circulating hormones that have melanocyte stimulating activity occurs in hyperthyroidism, Addison's disease, and acromegaly. In women who are pregnant or taking oral contraceptives there may be an increase in melanocytic pigmentation of the face. This is known as melasma (or chloasma) and occurs mainly on the forehead and cheeks. It may fade slowly. Sometimes a premenstrual darkening of the face occurs.

Increased deposition of haemosiderin is generalised in haemochromatosis. Localised red-brown discoloration of the legs is seen with longstanding varicose veins. It also occurs in a specific localised pattern in Schamberg's disease, when there is a "cayenne pepper" appearance of the legs and thighs.

Neoplasia

Lymphomas may be associated with increased pigmentation. Acanthosis nigricans, characterised by darkening and thickening of the skin of the axillae, neck, nipples, and umbilicus, occurs with internal cancers, usually adenocarcinoma of the stomach. It is also seen in acromegaly. There is a benign juvenile type. Pseudoacanthosis nigricans is much more common, consisting of simple darkening of the skin in the flexures of obese individuals; it is not associated with malignancy.

How To Reduce Acne Scarring

How To Reduce Acne Scarring

Acne is a name that is famous in its own right, but for all of the wrong reasons. Most teenagers know, and dread, the very word, as it so prevalently wrecks havoc on their faces throughout their adolescent years.

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