Causes and risk factors
Causes of hyperpigmentation include hormonal changes – an increase in circulating hormones that have melanocyte stimulating activity occurs in diseases like hyperthyroidism, Addison’s disease, and acromegaly. In pregnant women or those taking oral contraceptives, there may be an increase in melanocytic pigmentation of the face. This is known as melasma [or chloasma]. Sometimes a premenstrual darkening of the face occurs. Hereditary causes – there may be localized well-defined pigmented areas in neurofibromatosis. Increased pigmentation with a bluish green color occurs over the lumbosacral region in the newborn infants known as Mongolian blue spot. In Peutz–Jeghers syndrome there are pigmented macules associated with intestinal polyposis in the oral mucosa, lips, and face. Localized reddish-brown discoloration of the legs is seen with chronic varicose veins. It also occurs in Schamberg’s disease, where there is a “cayenne pepper” appearance of the legs and thighs. Neoplasia is one of the causes. Lymphomas may be associated with hyperpigmentation. Acanthosis nigricans is characterized by darkening and thickening of the skin. Darkening of the skin may be due to the deposition of bile salts in liver disease, iron salts [hemochromatosis], drugs, or metallic salts. Hyperpigmentation can occur post inflammation. Few examples are acute eczema, fixed drug eruptions, lichen planus, etc. Use of certain drugs can cause darkening of the skin. Malabsorption and deficiency diseases like pellagra and scurvy also can cause hyperpigmentation. Sun exposure can also lead to dark skin.
Clinical presentation
The clinical presentation depends upon the underlying cause. The hyperpigmentation can be focal or widespread. Focal hyperpigmentation, i.e., which is limited to a specific area is seen post inflammation, injury, melasma, or acanthosis nigricans. Melasma occurs on the forehead and cheeks. It may fade slowly. Specific localized pattern is seen in Schamberg’s disease, where there is a “cayenne pepper” appearance of the legs and thighs. Acanthosis nigricans is characterized by darkening and thickening of the skin of the axillae, neck, nipples, and umbilicus. Increased pigmentation with a blue tinge occurs over the lumbosacral region in the condition called Mongolian spots. Congenital conditions may be localized by well-defined pigmented areas in neurofibromatosis with “cafe au lait” patches. Widespread hyperpigmentation is caused in cancers, hormonal changes, drugs, and other systemic disorders. Lymphomas can arise in or invade the skin. Pruritus may be associated with the disease. Age spots, freckles are common type of hyperpigmentation.
Investigation
Medical history by the patient and clinical examination by the dermatologist helps in diagnosis. Routine hemogram is recommended. TFTs may be done. Skin biopsy may be required. LFT may be advised.
Treatment
Treatment depends upon the underlying cause. Hormone replacement is required in case of hormonal changes. Treatment for cancer should be given. Drugs that cause dark skin should be avoided. Deficiencies must be treated by dietary supplements. Corticosteroid creams or ointments will also help in managing hyperpigmentation. Topical ointments are effective for people with small areas of hyperpigmentation, especially on the face and neck. Avoiding exposure to direct sun, using sunscreen lotions, and protective garments contribute further to the treatment. Surgery involves skin grafts which are used for small hyperpigmented areas. Tattooing can be an option for people who want to cover up affected parts of skin.
Other Modes of treatment
The other modes of treatment can also be effective in treating hyperpigmentation. Homoeopathy is a science which deals with individualization and considers a person in a holistic way. This science can be helpful in combating the symptoms. Similarly, the Ayurvedic system of medicine which uses herbal medicines and synthetic derivates is also found to be effective in treating hyperpigmentation.
