Vitiligo is a skin disorder involving the appearance of white patches on skin due to a loss of pigmentation, skin may otherwise appear naturally healthy. This hypopigmentation occurs as a result of the destruction of the cells, called melanocytes, that make the skin’s brown pigment (melanin).
What causes vitiligo?
The cause of vitiligo is not known but there is speculation that it is an autoimmune disease which results in the body destroying its own cells, in this case the melanocytes that produce skin pigment. As well as the skin problems caused by vitiligo, the condition can also affect the mucous membranes in the mouth, nose and eye.
Autoimmune disorders are thought to have a hereditary aspect with certain genes making a person more prone to developing an immune system dysfunction where the body mistakenly attacks itself. Other theories regarding vitiligo causes include the idea that the melanocytes destroy themselves, and that physical trauma (sunburn, for example) or emotional trauma (stress) can trigger vitiligo. There is no substantive evidence to suggest that either hypothesis is correct.
Damage from other skin diseases, such as psoriasis, and eczema may contribute to the causes of vitiligo, although some people appear to have a genetic predisposition to the dermatological condition. There are also some skin specialists that have put forward the hypothesis that the melanocytes destroy themselves, whilst other dermatologists believe that trauma from sunburn, and even emotional distress can be a cause of vitiligo. There is no clear evidence to support such theories however, which can make vitiligo very difficult to treat.
The most likely explanation for vitiligo is that a combination of factors occurs which result in abnormal melanocyte function and the death of these pigment-producing skin cells. It is possible that a neuropeptide may damage melanin and lead to the white skin patches found in vitiligo. The neuropeptide is thought to be released in the skin following physical trauma, or during emotional stress.
Emotional stress also affects the hypothalamic-pituitary-adrenal axis (the HPA axis), which also involves the thyroid gland. Chronic stress in this system can lead to a reduced ability to cope with infection, demands for energy, repair, and growth, and lead to abnormal responses in the immune system where autocytotoxicity then arises.
Other factors that have been suggested as possible causes of vitiligo range from the use of certain medications over long periods, abrasion from clothes being too tight (on the waist particularly it seems), and the use of rubber gloves or other such protective wear in certain types of employment.
Researchers at the Laboratory for Investigative Dermatology in New York investigated the connection between cellular immunity and the pathogenesis of vitiligo. Wang, et al (2011), discovered that there were increased numbers of particular types of immune-system cells in the areas of the vitiligo lesions (white skin spots) which may be facilitating the development of vitiligo.
Immune system T cells and inflammation-related dermal dendritic cell subsets were elevated in the skin biopsies taken from vitiligo patients. In noting the concentration of Langerhans cells, which then drive Th17 activation in vitiligo, it may be that future research may focus on this immune system activity as a potential target for vitiligo treatment.
Elevated tissue mRNA (mitochondrial RNA) levels of interleukin-17A and IL-1Beta mRNA at the leading edge of the vitiligo white patches suggests that specific cellular immune elements play a key role in the inflammation which ultimately destroys the melanocytes in the skin.
A different set of researchers, working in France, have proposed a theory of melanocytorrhagia as the mechanism behind vitiligo (Cario-André , et al, 2007). This hypothesis details the chronic detachment of the the pigment-producing skin cells and, thus, the loss of these cells from the skin due to autoimmune, neural, and impaired redox mechanisms following physical trauma and free-radical damage.
Essentially, the melanocytes are unable to ‘stick’ in the skin and the depigmentation occurs, leading to the symptoms of vitiligo. Although the melanocytorrhagic hypothesis does not fully explain the cause of vitiligo in terms of the reason for the defect in the skin cells, it may offer a target for future vitiligo treatment.
Who Gets Vitiligo?
Vitiligo is indiscriminate it seems in terms of who it affects, with one in every hundred people thought to suffer from the skin condition. There are an estimated 1-2 million people in the US with vitiligo, with half developing vitiligo before their twentieth birthday and most developing it prior to their fortieth birthday. Vitiligo affects people of all races, genders, ages, and ethnicities.
Those with certain autoimmune system disorders, such as hyperthyroidism or Hashimoto’s Thyroiditis, have a higher risk of developing vitiligo, as do those with pernicious anaemia, alopaecia areata, and Addison’s disease (where the body does not produce enough corticosteroid hormone). Most people who suffer from vitiligo do not have an autoimmune disorder however, but many will have a close relative with the condition as vitiligo does run in families. However, even if one or both parents have the condition, this does not always lead to vitiligo in children, although the risk of developing the skin condition is higher.
Patients with vitiligo may have a copy of the same gene (NALP1) that is often present in those suffering from hypothyroidism (an under-active thyroid gland). Other skin conditions, and disease affecting the skin as part of their pathology, are also associated with this particular gene on chromosome 17p13, including psoriasis and systemic lupus erythematosus (which can cause a distinctive butterfly rash on the face). As such, it may be that a vitiligo patient’s physician deems it necessary to conduct regular screening of thyroid function. Blood tests to check for the levels of T3, T4, and Thyroid stimulating hormone may be wise for patients with vitiligo.
The main symptom of vitiligo is the appearance of white patches on the skin, usually in areas where the skin is commonly exposed to the sun. The white skin spots can appear suddenly or gradually on the hands, feet, face, lips, and arms, along with other areas such as in the armpits and the groin, the navel, genitals, rectal region, and inside the nostrils.
Those with darker skin may find that the inside of their mouth also loses pigmentation, and the white patches are often more apparent in those with naturally darker skin. The skin continues to feel normal and there is usually a darker border around the area of skin discoloration.
The white patches are usually irregular and both sides of the body are equally affected, which may help identify other causes of depigmentation should a distinctive pattern emerge. There are three common patterns of vitiligo seen in patients:
Focal Pattern: where there are a limited number of areas affected by the white skin patches
Segmental Pattern: where the white skin spots develop on just one side of the body
Generalised Pattern: where depigmentation occurs across the body in a symmetrical fashion (this is the most common type of vitiligo seen).
Vitiligo progression may be slow in some cases and quite rapid in others, with a number of patients finding that the white patches of skin do not grow or spread at all after they first arise. Anecdotal evidence suggests that stress, both physical and emotional can contribute to vitiligo symptoms and is connected to a more rapid spreading of the white skin spots.
Once the depigmentation occurs however, it is very difficult, and in some cases considered impossible, to reverse. Determining if the whitening of the skin is vitiligo-related means that a physician will ask questions about a patient’s recent history, such as whether they have experienced sunburn, skin trauma, emotional stress, or physical illness in the two or three months prior to the development of the skin condition.
White Patches on Skin
One of the most famous sufferers of vitiligo, Michael Jackson, had extensive loss of pigmentation, but many sufferers have smaller white patches. The incidence in men and women appears to be roughly equal and the condition affects people of different ethnic backgrounds equally, although those with darker skin may be more likely to notice the effects earlier than those with naturally pale skin.
Anecdotal evidence suggests that emotional stress and trauma can accelerate the progression of vitiligo although no research evidence is available to support this hypothesis due to the ethical constraints of such research.
Diagnosing vitiligo usually involves a medical history and physical examination. Family medical history will also form part of the diagnosis as a doctor will likely ask if others in the patient’s family suffer from skin diseases or autoimmune diseases. For patients with grey hair they may be asked if their hair lost pigment prior to their 40th birthday, and all patients are asked about skin trauma such as sunburn, rashes, and things such as eczema and psoriasis.
Patients with other skin problems may be asked about their eczema treatment, or psoriasis treatment using topical steroid creams or other therapies as well as sensitivity to the sun, current and previous emotional stress and physical illness.
Physicians will also typically ask about the health of a patient’s family members. This is because vitiligo is thought to be hereditary in many, if not all, cases. Where other family members, or the patient themselves, have autoimmune diseases there may be a higher degree of suspicion for vitiligo.
Patients with grey hair will usually be asked when their hair lost pigmentation as another common symptom of vitiligo is an early greying of the hair, usually before the age of thirty-five or forty. This greying may affect the scalp hair alone but can also cause the eyelashes, eyebrows, beard, and other body hair to lose pigmentation..
Following medical history, the doctor may collect a blood sample and take a small sample of skin (a skin biopsy) for laboratory testing. Examining the skin under a microscope may reveal a complete absence of melanocytes (the skin cells that produce pigment) which would confirm a diagnosis of vitiligo.
Should there be signs of inflammation in the skin cells however, this may suggest to the physician that the hypopigmentation is connected to a different condition which may respond to alternative treatment. The kind of tests carried out will be determined by each individual’s circumstances but may include hormonal tests to check thyroid function as hyperthyroidism is linked to vitiligo.
Those with Addison’s disease are also more likely to develop the skin disorder than the general population and tests for adrenal function may be carried out. Patients with pernicious anaemia also have a higher rate of vitiligo, and the physician may order tests for vitamin B12 levels to rule this out as a cause of vitiligo.
Where available, a physician or dermatologist may use a Wood’s light to check the skin. This handheld device emits ultraviolet light which causes depigmented areas of skin to glow bright white. Some patients may also have an eye examination carried out to check for uveitis, an inflammatory disorder in the eye which can co-exist with vitiligo. Blood tests for antinuclear antibodies may also be run to investigate the possibility of autoimmune disease in the patient with treatment for vitiligo dependent on the results of all such tests.
Doctors may also use a blood sample to test hormone levels and vitamin B12 status, take a small skin sample (biopsy), and conduct an eye examination.
Treatments will usually not be prescribed until the test results have returned but the doctor will likely discuss possible vitiligo treatments with a patient first to determine any preference in how to approach the management of the skin condition.
Continue Reading —> Vitiligo Treatment
Jin Y, Mailloux CM, Gowan K, Riccardi SL, LaBerge G, Bennett DC, Fain PR, Spritz RA. NALP1 in vitiligo-associated multiple autoimmune disease. N Engl J Med. 2007 Mar 22;356(12):1216-25.
Wang CQ, Cruz-Inigo AE, Fuentes-Duculan J, Moussai D, Gulati N, Sullivan-Whalen M, Gilleaudeau P, Cohen JA, Krueger JG. Th17 cells and activated dendritic cells are increased in vitiligo lesions. PLoS One. 2011 Apr 25;6(4):e18907.
Cario-André M, Pain C, Gauthier Y, Taïeb A. The melanocytorrhagic hypothesis of vitiligo tested on pigmented, stressed, reconstructed epidermis. Pigment Cell Res. 2007 Oct;20(5):385-93.
‘Vitiligo on legs’ picture courtesy of Grook Da Oger, 2009.
‘White Rabbit’ picture courtesy of TJ Blackwell, 2010.
Vitiligo picture courtesy of James Heilman, MD.