Last Updated on 16th August 2024 by Caroline Haye
Some of the terms used in connection with vitiligo can be a bit baffling at first. Especially for those of us who don’t have a medical background. So I have put together a glossary of vitiligo terminology, featuring some of the most frequently used words. I hope you find it helpful as you trawl the internet in search of information on this condition. (You may also want to check out my FAQ pages to help you in your research.)
AETIOLOGY (alternative spelling: ETIOLOGY) – the study of the causes of a disease.
ANTIOXIDANT – an enzyme or other organic substance, as vitamin E or beta carotene, capable of counteracting the damaging effects of oxidation in animal tissues.
AUTO-IMMUNITY – a misdirected immune response. One that results in the production of antibodies that mistakenly attack the tissues of your own body. (Most experts classify vitiligo as an auto-immune disease. One in which the body’s defence system attacks its own pigment–producing cells.)
CATALASE – an antioxidant, an enzyme that breaks down hydrogen peroxide into oxygen and water.
CUTANEOUS – relating to the skin.
EPIDERMIS – the outer layer of the skin.
FREE RADICAL – free radicals are molecules with unpaired electrons. In their quest to find another electron, they are very reactive and cause damage to surrounding molecules.
HYDROGEN PEROXIDE – a combination of hydrogen and oxygen. Its chemical description is H2O2. In high concentrations it can be unstable and toxic. In lower concentrations it can serve as a disinfectant, antiseptic or bleach. It was once the wound ceanser of choice in many households. But this is no longer the case because it can damage live skin. Organisms naturally produce hydrogen peroxide as a by-product of oxidative metabolism. Hydrogen peroxide plays a role in our immune responses. And research shows that vitiligo sufferers typically have higher levels of it on their skin than people without vitiligo.
HYPERPIGMENTATION – the darkening of an area of skin or nails caused by increased melanin.
HYPOPIGMENTATION – the loss of skin colour due to melanin depletion.
HYPERTHYROIDISM – (often referred to as an overactive thyroid gland) is a condition in which your thyroid produces too much thyroxine. This is the hormone that helps regulate the adrenal system, plays a role in energy, normal growth and development, as well as the ability to maintain a healthy weight, and in mood stability.
HYPOTHYROIDISM – (often referred to as an underactive thyroid gland) is a condition in which your thyroid produces too little thyroxine. Too little of this hormone also negatively impacts the same functions as too much.
LESION – an abnormal change involving any tissue or organ due to disease or injury. Vitiligo lesions are white patches of skin.
LEUCODERMA (alternative spelling: LEUKODERMA) – localised loss of pigmentation in the skin. This can be due to a variety of causes, not just vitiligo.
MACULE – a patch of skin that has changed colour but is usually not raised. This is a characteristic feature of various diseases, including vitiligo.
MELANIN – the brown pigment that gives human skin, hair, and eyes their colour. Dark-skinned people have more melanin in their skin than light-skinned people have. Melanin is produced by cells called melanocytes. It provides some protection again skin damage from the sun. Melanocytes increase their production of melanin in response to sun exposure. Freckles, which occur in people of all races, are examples of small, concentrated areas of increased melanin production.
MELANOCYTE – Melanocytes are cells located in the epidermis that are responsible for producing melanin. But they also occur throughout the body and internal organs where they perform a wider range of functions.
NON-SEGMENTAL VITILIGO – the most common type of vitiligo, in which white patches develop in a broadly symmetrical pattern. New patches usually appear over time. And these may spread over large portions of the body or limit themselves to a particular area.
OXIDATIVE STRESS – an imbalance between the production of free radicals (see definition above) and antioxidants. This imbalance means the body cannot counteract cellular damage and a build-up of hydrogen peroxide.
PIGMENT – a substance that gives colour to all animal or plant tissue. In the case of the human body, various pigments are responsible for the colours of skin, eyes, and hair. And one of these pigments is melanin.
PSEUDOCATALASE – (also called Pcat for short) is an antioxidant vitiligo treatment cream. It can help to reduce epidermal hydrogen peroxide in vitiliginous skin. Pseudocatalase is usually used in combination with narrow band UVB light therapy.
SEGMENTAL VITILIGO – differs in appearance, aetiology and treatment from non-segmental vitiligo. It tends to affect one particular section of skin (or possibly several). And it is unilateral instead of symmetrical in its distribution.
SOD (superoxide dismutase) – another powerful antioxidant with similar benefits to catalase. (See definition of catalase above.)
THYROID – the thyroid gland is an endocrine gland in your neck. It makes two hormones that are secreted into the blood: thyroxine (T4) and triiodothyronine (T3). These hormones are necessary for all the cells in your body to work normally. Thyroid disorders are very common. They are more common in women, although anybody can develop them. About one in twenty people has some kind of thyroid disorder, which may be temporary or permanent.
TOPICAL – A topical medication is a treatment that is applied to body surfaces such as the skin. It is usually a cream, foam, gel or ointment.
UVA – UVA is a long wavelength (320-400nm) of ultraviolet light. This wavelength penetrates both the epidermis and dermis (i.e. both the upper and lower levels of the skin). It causes skin tanning, but also the unwanted concerns of brown spot formation premature wrinkling and risk of skin cancer. Most commercial tanning beds emit UVA light.
UVB – UVB is a short wavelength (290-320nm) of ultraviolet light. This wavelength affects primarily the epidermis and does not penetrate as deeply as UVA. But it can cause sunburn and also carries the risk of skin cancer. (NB-UVB or Narrow Band UVB is ultraviolet light in a narrow band 311nm to 313 nm. This wavelength is now the preferred form of light therapy. It is more effective, faster acting, and may be safer than other UV light treatments.)
VITILIGINOUS – affected by vitiligo (e.g. vitiliginous skin).
WOOD’S LAMP – a.k.a. black light or ultraviolet light. This lamp can aid diagnosis and identification of vitiliginous lesions more clearly than normal lighting conditions. Skin with vitiligo, when exposed to a black light, will glow yellow, green or blue. This is in contrast to healthy skin which will have no reaction.
I also recommend the description of vitiligo in plain language available on the Cleveland Clinic website.
