- What is vitiligo, broadly how is it treated?
Vitiligo is also known as 'leucoderma'. In India , it is called 'safed kod' or 'safed dag' and is considered as a social stigma. Vitiligo is appearance of single or multiple depigmented patches on any part of the body.These patches gradually increase in size & cause lot of psychological stress in the patient. It is an auto-immune condition and may have a genetic predisposition. Treatment of vitiligo usually takes a long time. Medical treatment helps arrest the spread of depigmentation and in some cases, may bring back the pigmentation. In majority of the cases, medical therapy only achieves stabilization of the vitiligo patch but fails to cause repigmentation. However, repigmentation in cases of 'stable vitiligo' can be achieved by various dermatosurgical techniques.
- What is is the role of puva in vitiligo?
PUVA therapy enhances skin re-pigmentation. An oral psoralen compound is given to the patient. Two hours later , the de-pigmented patch on his body is exposed to ultraviolet-A (UVA) rays, for a fixed time duration. This should be supervised by a medical personnel. If UVA is not available then the patch is exposed to sun rays. The latter is known as PUVA SOL therapy.Treatment with UVB rays is another option. The most recent modality is treatment with Excimer laser.
- When is the patient fit for surgery?
When the de-pigmented patch does not increase in size for a period of two years, it is said to be stable. This is the right time to perform vitiligo surgery. If the patch is growing or is in an active phase, it needs treatment with medicines and / or PUVA till it stops growing.
- What are the various surgical modalities available?
Method to be used depends on the type and site of lesion. Hence, selection of the appropriate surgical technique is important for good cosmetic results.
- Miniature punch grafting.
- Ultra thin skin grafting.
- Suction blister grafting.
- Therapeutic spot or regional dermabrasion .
- Melanocyte culture and transplantation.
- What is miniature punch grafting?
Multiple thin grafts of 2 - 2.5 mm diameter are taken from the donor site by special punches and grafted on to the diseased area. Once the grafts are 'taken up' the patient is advised to take PUVA or PUVA SOL. Re pigmentation occurs in 3 - 6 months and good cosmetic result is obtained.
- What is ultra thin skin grafting?
A very thin skin graft (ultra thin) consisting of epidermis is grafted onto the dermabraded or laser ablated part of stable vitiligo. The graft falls off by 8 -10 days but there takes place a cellular uptake of melanocytes on to the abraded skin which gradually starts pigmenting, it takes 2 - 3 months for the pigmentation to merge and match with the surrounding skin color.
- What is suction blister grafting?
A prolonged suction (negative pressure) is applied to the donor site this raises a large bleb and a thin graft containing only the epidermis is obtained. This is grafted on to the dermabraded recipient surface. This technique is time consuming but gives good cosmetic results.
- What is melanocyte transplantation?
Melanocytes are cultured in artificial culture media. The de pigmented recipient site is dermabraded or laser ablated and the melanocyte suspension is applied to it. The area is covered with a collagen dressing and immobilized. Large areas can be covered with this method and excellent cosmetic results obtained.
- Though the patch resembles the surrounding normal skin, it may permanently fade or acquire a bluish hue after 1 - 2 years which is distinctly noticeable and may become unacceptable. Hence, tattooing is usually not advised unless the patch is in an inoperable site.
Epidermal cell suspension technique
Vitiligo is the most common depigmenting dermatosis that affects approximately 0.5 to 1% of the general population regardless of race and sex. Treatment of vitiligo by transplantation of autologous pigmented skin grafts or blister roofs has been carried out for about 45 years. Punch grafts can give rise to cobblestone-like scars, but this has been avoided by using blister roofs. The blisters have been produced on normal skin by suction and transplanted to white areas.
The original technique for dissociating human skin samples involved treatment at 4oC with a 0.25% trypsin solution to shear off remaining dermis and to loosen cell-to-cell adhesion, followed by vigorous mechanical dissociation in plasma of the patient. Treatment at high trypsin concentration and 37oC followed by vigorous agitation dissociates the epidermis almost completely. However, the yield of intact cells is lower and the cells exhibit numerous vacuoles throughout the cytoplasm. In contrast, in our method, mild trypsinization of the epidermis in the presence or not of EDTA at low enzyme concentration and 4oC produces an incomplete dissociation but nevertheless gives a higher yield of single viable cells. The beneficial effect of this treatment can be explained by the fact that endocytotic uptake of trypsin is negligible at 4oC, whereas trypsin taken up at 37oC persists in the cells for up to 48 hours