Leukoderma
Leukoderma or vitiligo as it is sometimes called, is a chronic skin condition that causes loss of pigment leading to pale spots of skin. Leukoderma can be described as an autoimmune skin disease where the body destroys its own pigment cells, melanocytes. After the pigment disappears, small or even larger areas of skin become white with sharp margins where they join unaffected parts of skin. The hair in these areas also grow white rather than pigmented. Leukoderma is more noticeable during summer when the normal skin darkens. The causes for leukoderma could be a combination of genetic and environmental factors. Inheritance seems to be a dominant trait for this condition.
Leukoderma may also occur at sites of injury to the skin and may show itself as scars or burns. Recent studies suggest that leukoderma could be caused by the development of an antibody to an enzyme in the pigment cell. Leukoderma may be caused due to several other factors as well - congenital as in tuberous sclerosis, partial albinism and Piebaldism and Waardenburg's syndrome. The immunological causes of leukoderma are Vitiligo and Halo mole. Thermal burns, Dermatitis or eczema and Psoriasis may also result in leukoderma. Infectious conditions such as Pityriasis versicolor, leprosy, lichen planus and syphilis could also result in leukoderma. Some occupational hazards that could cause leukoderma are exposure to depigmentation agents such as tertiary butyl phenol and exposure to chemicals.
The spots can spread, shrink or remain the same. It is often noticed that patches occur in symmetrical fashion across both sides of the body. Some times mild trauma to an area of skin can cause new spots as around ankles caused by friction due to shoes or sneakers. Corticosteroid ointment or cream of appropriate strength is used depending on the site involved. Normally a mild steroid is used on the face and a stronger one for the trunk and limbs. A specialized form of light treatment PUVA is also of value to some patients.
Pigmentation
Melanin is responsible for imparting color to the skin, hair and iris of the eyes. Levels of melanin depend on race and amount of sunlight exposure. Melanin production increases with exposure to the skin so as to protect the skin against harmful ultraviolet rays. Skin pigmentation disorders occur as a result of the body producing either too much or too little melanin. Skin pigmentation creates a darker or lighter skin tone that may be blotchy and uneven. Sun damage is probably the leading cause of skin pigmentation problems. Other factors include drug reactions, hormonal changes, genetic factors and medications.
Hormonal therapy, childbirth or birth control pills can cause skin pigmentation changes. Many people suffer from skin pigmentation problems as a result of locally increased skin pigment production. They appear as age spots, moles, liver spots or hyper pigmentation after local skin damage. Freckles are another variation in pigmentation of the skin. They are caused but by uneven release of the pigment.
Hypopigmentation or loss of skin pigmentation is a condition where the body does not produce sufficient melanin. Sometimes after an ulcer, blister, burn, or infection heals, the skin loses some of its pigment in that area. Albino is one who suffers total hypopigmentation at birth.
Vitiligo: Vitiligo is another form of hypo pigmentation caused by the loss of pigment-producing cells in the skin (melanocytes). These white patches are very sensitive to the sun. This skin pigmentation disorder affects nearly 2% of the population and is more evident in those with darker skin. Some scientists believe vitiligo may be caused by an autoimmune disorder. It is also linked to hyperthyroidism and Addison's Disease that affects the adrenal glands.
Hyper Pigmentation is a condition where the body produces too much melanin thereby causing it to become darker than usual. Hyper pigmentation can occur due to excessive sun bathing or drug reactions. Many a time wounds and scars leave a darker patch of skin. Birthmarks, moles, and aging spots are also indications of hyper pigmentation. It is important to keep on the alert for any change in size, color or texture for indications of skin cancer.
Lichen Simplex Chronicus: This skin pigmentation disorder is characterized by dark patches of skin accompanied with severe itching. This can lead to permanent scarring and infection if untreated.
Melasma: This hyper pigmentation condition is a fallout of pregnancy hormones. A dark mask appears over the cheeks, bridge of the nose and the neck. This skin pigmentation condition is also known as chloasma and can be treated with prescription creams and over-the-counter products.
Birthmarks: This type of skin pigmentation appears at birth or in the few weeks following birth. These birthmarks do not generally pose any health risks.
Port-wine Stains: These skin pigmentation spots are caused by abnormal development of capillaries and appear as a red or purple mark on the body.
Poikiloderma: This skin condition is characterized by areas of increased and decreased pigmentation; indicative of sun damage.
ANA blood test
Antinuclear antibodies (ANA) refer to the unusual antibodies that are detectable in the blood. ANA are gamma-globulins type of antibodies that are found in patients with certain autoimmune diseases. ANA are directed against certain components found in the nucleus of a cell in the body. These antibodies have the capacity of binding certain structures within the nucleus of the cells. The ANA test was first designed by Dr.George Friou in 1957. The laboratory blood test exposes the antibodies in the serum of the blood to cells. It is then determined whether or not antibodies are present that react to various parts of the nucleus of cells. Hence the term 'anti-nuclear' antibody is used.
Fluorescence techniques are adopted to detect the ANA antibodies in the cells. Thus ANA testing is sometimes referred to as fluorescent antinuclear antibody test (FANA). Nowadays, a method to detect antinuclear antibodies called enzyme linked immunosorbent assay (ELISA) is replacing the previous method of immunofluorescent assay technique. The ELISA method is less likely to produce false positive ANA result than the previous method.
Patterns also give doctors a clue as to the type of illness to look for while evaluating a patient. For instance, the disease Scleroderma shows in nucleolar pattern. If a person does not have any autoimmune disease, it is defined in speckled pattern. An ANA blood test is used in patients who might be suffering from Sjogren's syndrome, rheumatoid arthritis, polymyositis, scleroderma, Hashimoto's thyroiditis, juvenile diabetes mellitus, Addison's disease, vitiligo, pernicious anemia, glomerulonephritis and pulmonary fibrosis. ANA can also be found in patients with conditions that are not considered autoimmune diseases such as chronic infections and cancer.
The result of ANA test is expressed in titers. A titer of 1 to 80 (1:80) means that antibodies could be last detected when 1 part of the blood sample was diluted by 80 parts of another liquid. Usually this other liquid is a diluted salt solution. A larger second number indicates that the antibodies are present in greater concentration. Therefore a titer of 1 to 320 indicated higher concentration of antibodies in the blood than a titer of 1 to 80. The normal values of ANA blood test is : Titer below 1: 20 or 1:40 depending on the test method used.
Positive ANA test result is suggestive of autoimmune disease. It can also mean that the patient has drug induced lupus. Some drugs and infections can also induce false positive ANA test results. Steroids can cause a false-negative result. Medications, especially antibiotics such as isoniazid, penicillin, and tetracycline, birth control pills, lithium and some diuretics such as chlorthalidone can interfere with the test and affect the accuracy of the ANA test result.
Bibliography / Reference
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