Dark spots on skin, especially on the face can be very embarrassing. It is important to know what really causes it. Most of the cases of dark pigmentation are acquired either by excess sun exposure, some diseases, drugs, or hormonal changes. There are few diseases that are caused by defects in the genes and may pass through families. In this article we will only focus on few of those diseases that are influenced by genetic factors. There may also be several other diseases of pigmentation caused by genetic defects that have not be discussed here.
Freckles
Freckles are small light brown spots seen in sun-exposed areas. They are more common in fair skinned people and more prominent during summer while fading during winter. Freckles are harmless and rarely develop into skin cancer. But if you see any change in freckle color, size and shape contact doctor immediately.
Lentigines
Lentigines are tiny light brown to jet black in color usually seen in sun exposed or artificial source of ultra violet radiation as in the case of tanning beds and photo-chemotherapy. Unlike freckles they usually do not fade during winter months.
Xeroderma Pigmentosum
Xeroderma Pigmentosum is characterized by sun sensitivity, photophobia, early freckling, and neoplastic changes on sun-exposed areas. One may develop several small freckles-like hyperpigmented spots on sun-exposed areas. XP may start as early as first 1-2 years of life. It is estimated that those who develops XP early in their life have greater risk of squamous cell carcinoma, basal cell carcinoma, or melanoma.
Cafe Au Lait Spots
Café au lait spots are light to dark brown birthmarks with smooth or irregular border. They are usually associated with neurofibromatosis type 1, a multisystem genetic disorder characterized by the growth of tumors along nerves in the skin, brain, and other parts of the body.
Peutz–Jeghers Syndrome
Peutz-Jeghers syndrome is genetic disorder characterized by the development of small, flat, brown or dark blue spots on lips, inside and around the mouth, near eyes, nostrils and fingers with multiple polyps on stomach and intestines. These pigmentations usually appear during early childhood (not at birth). Lips spots may fade with time. Multiple polyps can cause severe problems like abdominal pain, bowel obstruction and chronic bleeding. People with Peutz-Jeghers syndrome have very high risk of developing intestinal cancer, stomach cancer, colorectal cancer and pancreas cancer during their lifetime than general population.
Albright’s Syndrome
Albright’s syndrome is a genetic disorder associated with fibrous dysplasia of bones, hormonal problems, skin pigmentation (café-au-lait spots) and premature puberty.
LEOPARD Syndrome
LEOPARD syndrome is a complex genetic disorder characterized by Lentigines, Electrocardiographic conduction abnormalities, Ocular hypertelorism, Pulmonary stenosis, abnormalities of genitalia, Retardation of growth and Deafness. The characteristic lentigines can be seen early during first few months of life and occurs in high numbers. Clinical diagnosis of LEOPARD syndrome is done by facial features along with other cardiac abnormalities as stated above.