Hyperpigmentation is a condition where parts of the skin turn darker in color than surrounding areas. These dark patches are generally seen on the face, hands, shoulders, or the neck area of an individual. These spots are usually referred to as liver spots, solar lentigines, pregnancy mask or freckles. Some kinds of hyperpigmentation spots could turn cancerous if not treated appropriately. A dermatologist could help distinguish hyper pigmentation from regular tanning or sunburn and provide effective treatment.
Hyper pigmentation causes
Melanocytes present in the skin's epidermis produce melanin which is the pigment responsible for the color of skin, eye and hair of an individual. Hormonal, physical changes or environmental factors trigger melanocytes to produce excessive melanin. This imbalance in production also affects the melanocyte's ability to distribute melanin evenly across the skin's epidermis. Therefore the excess melanin usually forms clusters and the skin tends to appear darker in the melanin concentrated areas, leading to uneven skin tone and darker areas.
Hormonal changes occurring during pregnancy and menopause can trigger excess melanin production. Diseases like hypothyroidism and Addison's disease can set off melanocyte stimulating hormones. Excessive sun exposure can play havoc on melanin production. Some medications such as those for insomnia, infertility, hypertension and oral contraceptives can cause hyperpigmentation.
Creams containing Hydroquinone, alpha Hydroxyl acid, licorice, green tea extracts or Retinol are prescribed for topical application. Chemical peels and skin dermabrasion are done to improve the skin tone. Laser procedures can work on melanin pigments.
Also known as a mole, nevi is a benign growth that could appear like hyperpigmentation of the skin, colored macules, plaques or papules. Nevi are mostly congenital. They are confined to a particular area of the skin. They are also commonly referred to as birthmarks or beauty marks. Benign nevi typically means that the specific pigmented skin portion has not shown any signs of abnormality that is typical of skin cancer.
How do nevi occur?
Development of nevi is influenced by age of the person, environmental factors like sun exposure, race and genetic factors. It can develop in any part of the body though it can be predominant in sun-exposed areas like arms, face or neck when compared to intermittently exposed areas like chest, back or legs. Though most nevi are benign, 25% of malignant melanoma arise from pre-existing nevi.
For males, nevi are concentrated on the face and neck while for females nevi are concentrated on thighs and upper arms. Dark skinned individuals have a low count of total body nevus when compared to light skinned individuals. However dark skinned individuals develop nevi on the palms and soles. Nevi count in males is higher than in females. Nevi count in children depends on the nevi count in their parents. Commonly acquired nevi follow the ABCDE rule:
Nevi can be classified into different types as listed below
Connective tissue nevus: This type is very rare to occur; they are fleshy deep nodules.
Epidermal nevus: They are present at birth (congenital), and appear on the upper torso of the body. They resemble the color of flesh and appear raised or like a wart.
Nevus sebaceous: A variant of epidermal nevus, it appears on the scalp. The affected scalp area becomes hairless and looks yellowish in color. Melanocytic nevus: Benign production of melanocytes i.e. the skin cells make the brown pigment melanin. Therefore most of the nevi are brown to black in color. They are the common type of nevi and are present in almost all adults. They could be congenital or may develop at a later stage in life. Different types under melanocytic nevus are:
Acquired melanocytic nevus: Acquired at a later stage in life; will not be present in birth or near birth period.
Congenital nevus: Present from birth or near birth.
Dysplastic nevus: Acquired type of melanocytic nevus and difficult to differentiate from melanoma. It could be an indicator for the risk of developing melanoma.
Nevi are grouped based on their location. The different categories are:
Compound: They are hyper pigmented macules located in the epidermis and dermis.
Junctional: They are hyper pigmented macules located in the epidermis.
Intradermal: They are brown/skin colored papules located in the dermis layer.
Diagnosis and treatment of nevi
Diagnosis of nevi is generally done through visual examination; a dermatoscope may also be used. While diagnosing nevi, the main concern lies in identifying a benign nevus from a dysplastic nevus and melanoma. If physical examination doesn't suffice, a skin biopsy may help in identification.
Treatment for benign nevi
In general, benign nevi need not be treated. However a few may want it to be treated for cosmetic reasons. You can opt for laser treatment with a qualified skin specialist.
Protecting skin with nevi
Wood's Lamp Examination
A wood's lamp examination helps the doctor confirm a fungal infection or bacterial infection. The doctor is able to determine the cause of any light or dark colored spot on the skin using this examination. This is a test using Ultraviolet or UV light to look more closely at the skin.
In case of fair skinned individuals, Wood's lamp can detect Vitiligo or any other depigmentation even when it is not visible to the eye under normal conditions. In case of detection, Vitiligo can be treated at an early stage even before it is visible to the normal eye, thereby minimizing treatment and preventing further expansion of the disorder.
What is Wood's lamp?
Also known as Black Light Test, or Ultraviolet Light Test, this is based on the use of ultraviolet light which is shined on the area being examined, when performed in a dark room. It emits ultraviolet light in the 365 nanometer range and when the light is shined directly on the area in darkness, the dermatologist looks for any change in color or fluorescence. While normal skin does not fluoresce under the light of the Wood's lamp, affected skin 'glows' in dark. if any fungal or bacterial infection or pigment is present, the Wood's lamp can strengthen or lessen the suspicion of a particular diagnosis based on the color of florescence of the affected skin being illuminated. Even subtle color changes can be detected very well using Wood's lamp.
You will be seated in a dark room usually in the dermatologist's office. The doctor turns on the Wood's lamp and holds it approximately 5 inches from the skin to look for color changes. It will reveal skin color changes not visible to the mere eye examination. The patient is advised not to look directly into the light when being examined. This portion of the examination usually lasts for less than a minute and the patient feels no discomfort from the examination.
Pre and post procedure
Before the Wood's lamp examination do not wash the area or apply any cream to the skin to avoid inaccurate results. Following the procedure, the dermatologist may decide to treat the skin condition based on the results of the Wood's lamp examination. Additional tests are sometimes done to arrive at the correct diagnosis. No aftercare is recommended specific to the examination and depending on the result of the examination the physician may recommend treatment of a skin disorder.
Why is Wood's lamp examination done?
Certain skin problems including bacterial and fungal infections, Porphyria, skin coloring changes in Vitiligo, head lice and nits, Erythrasma and other pigmentary disorders can be performed using this test.
The test also reveals different colors according to the type of the skin disease which includes:
Exposure to Ultra violet Light for prolonged duration can result in skin damage and cancer of the skin. But this test hardly lasts for a minute and the intensity of the light is minimal. Patients should avoid looking directly into the UV light and since the time for the procedure is very minimal - less than a minute - the procedure is well tolerated as there is no associated pain and no side effects as a result. Beware that the presence of other materials like certain kind of makeup, deodorants, perfume, body lotion or soap can also fluoresce leading to difficulty in arriving at a conclusive diagnosis. Equally if the room is not dark enough, it may present difficulty for proper examination. Not all bacteria or fungi show up under the UV light.
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Bibliography / Reference
Collection of Pages - Last revised Date: April 1, 2020