An adolescent may draw the attention of a parent to newly developed white patches on his or her skin. A young adult may become aware of areas of loss of skin pigmentation. Usually neither of them will have much by way of other symptoms. There might possibly be a slight itch, but this is not a major feature. However, the white patches are distressing, and they usually become bigger and more widespread. In the early stages, they may progress quite rapidly. The nature of the condition is progressive, although not always quickly.
Vitiligo usually starts between 10 and 30 years of age, although it may appear at any age. It occurs equally across genders and races, but the depigmentation will obviously be more apparent on a darker skin.
The condition is relatively common with 1–2% of the population having it (2 to 4 million Americans).
How Vitiligo is Diagnosed
History of the Vitiligo Symptoms
At what age did the lesions begin to appear, and on what part of the body? What has been the progress of the depigmented areas since their first appearance? Have they got bigger, spread in the same area, or generally are they all over the body? Are there any other associated symptoms? Is there a family history of vitiligo? Much can be gained from these questions that can help to point to a diagnosis of vitiligo, as opposed to a different cause of loss of skin pigmentation.
There are other issues which need to be broached. Vitiligo is frequently associated with autoimmune disorders, especially involving the thyroid, and diabetes. Questions related to normal functioning of thyroid and the like should be considered.
Physical Appearance of the Depigmented Areas
The white patches are clearly demarcated, they enlarge unpredictably, and they may occur anywhere on the body. The most frequent places are the feet, forearms, hands and face, especially around the mouth and eyes. They will often be more prevalent in areas of trauma or heavier wear and tear; for example, on the knees, elbows, wrists, backs of hands and ends of fingers.
In generalized vitiligo, mucous membranes (in the mouth, for example) may be involved (more apparent in a darker skinned person). In the case of vitiligo of the scalp, a localized patch of white hair will be seen.
Biopsy to Show Loss of Skin Pigmentation
Although the clinical appearance is generally adequate for a diagnosis to be made, there are times when a biopsy may be needed to clarify a questionable diagnosis. In vitiligo, the histology shows a complete absence of melanocytes and absolutely no pigmentation in the epidermis. This is as opposed to other, more inflammatory conditions (e.g. tinea versicolor) where one would see inflammatory cells and possibly signs of fungal infection.
Blood Tests
As vitiligo itself may be an autoimmune condition, or certainly may be associated with other autoimmune conditions, screening blood tests need to be done to eliminate the possibility of any of these conditions, such as hypothyroidism (as in Hashimoto’s disease), diabetes, pernicious anaemia (an inherent inability to absorb vitamin B12), Addison’s disease and alopecia areata. These tests include thyroid function, fasting blood glucose, full blood count and antinuclear antibody tests. Further tests may be done if indicated.
It is important while considering these tests, and getting a diagnosis, to realise that some of the other systems may be seriously affected by autoimmune conditions linked to vitiligo. These include:
- difficulties with eyes such as uveitis and iritis – these involve inflammation and pain; it is essential to visit an eye specialist during the investigation and management of the vitiligo
- hearing may be affected – the labyrinth in the inner ear contains melanocytes, which may also be depleted in vitiligo, thus affecting hearing.
Patients with malignant melanoma can have areas of loss of skin pigmentation mimicking vitiligo. These may be remote from the melanoma and appear to be a reaction of the body to produce T cells in its effort to fight the melanoma. The T cells appear to react to both the melanoma cells and healthy melanocytes, thus destroying them.
Classification of Vitiligo
The most commonly used classification of the appearance of vitiligo is based on the distribution of the lesions – localized, generalized or universal.
There are three types of localized vitiligo:
- focal vitiligo – concentrated area of white patches
- segmental vitiligo – distributed along an apparent dermatome; this occurs most commonly in children and there is generally no autoimmune disease
- mucosal vitiligo.
There are three types of generalized vitiligo:
- acrofacial vitiligo – involving fingertips and periorificial areas
- vulgaris vitiligo – widely scattered lesions
- mixed vitiligo – combinations of the above types.
People with universal vitiligo, which frequently occurs together with multiple endocrinopathy syndrome, have virtually no pigment, if any at all.
Differential Diagnosis of Vitiligo
There is a long list of conditions that can cause loss of skin pigmentation which may need to be eliminated before a definite diagnosis of vitiligo can be reached.
These include tinea versicolor, Addison’s disease, pityriasis alba, chemical leukoderma, halo nevus, leprosy, malignant melanoma, post-inflammatory depigmentation, following cortisone injection or cream, scleroderma, mycosis fungoides, tuberous sclerosis, Waardenburg syndrome, Vogt–Koyanagi–Harada syndrome, Alezzandrini syndrome, piebaldism, idiopathic guttate hypomelanosis, nevus anemicus (river blindness) and treponematosis.
The above tests will help to differentiate between the different possible causes of loss of skin pigmentation. Some of these conditions may have more symptoms than vitiligo. Some may be self-limiting, or respond to fairly simple treatment. For others the treatment is much more complex.
References
Groysman V, Sami N, 30 Nov 2009 Vitiligo (Online) Accessed 29 July 2010
MedicineNet.com, 31 July 2010 Vitiligo (Online) Accessed 31 July 2010
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