Ted Lain, MD, breaks down the use of the Vitiligo Area Scoring Index calculations to assess vitiligo severity.
Seemal Desai, MD: I appreciate you mentioning active and unstable vitiligo. I want to come back to that in just a minute, and I think that’s a good segue, Ted, because you’ve been involved in clinical trials in your practice. You and I have done a lot of these together. Nada just talked a lot about unstable, inflammatory vitiligo, and the question is: How do we assess vitiligo? How do we grade it? How do we measure it? How do you like to differentiate active versus stable, or are there ways to calculate severity?
Ted Lain, MD: First of all, I have to give Nada props for vitiliginous. I’ve never heard of that word. That is a great Scrabble word.
Seemal Desai, MD: Great word.
Ted Lain, MD: I’m going to put that into my memory now. The way we assess vitiligo in clinical trials, and now I do this in the clinic as well, is the Vitiligo Area [Scoring] Index, or VASI, which essentially is like a body surface area [BSA measurement] for psoriasis or eczema. One handprint is 1% of your body surface area. And so VASI, the F-VASI, Facial Vitiligo Area Scoring Index, this is 1% as well. Now, you multiply that by the degree of depigmentation. So 100% would be 100% depigmented, no pigmentation at all. If you have 1% of your face depigmented and that area is 100% depigmented, 1 times 100% is 1, so your F-VASI is 1. The thing to remember is in clinical trials, most of them for example that we’ll talk about, the inclusion criteria say that the F-VASI has to be at least 0.5 for many of them. How do we get to F-VASI of 0.5 if they have less than 100% depigmentation? You look at F-VASI, and you can multiply it by 90%, or 75%, or 50%, and that’s how you get the true F-VASI score. It is BSA times the degree of depigmentation, and that’s what the VASI measures.
Seemal Desai, MD: Yes, and the 1% trick is great because I can oftentimes tell my patients, if you’re at home and in between appointments and I’m not seeing you in 6 months, and you start noticing patches or an area that’s larger than the size of your palm, or multiple patches that can fit in the size of your palm, you need to come to the office.
Ted Lain, MD: That’s right.
Seemal Desai, MD: Nada, back to what you were saying, active, unstable disease, in my mind, I call that a vitiligo emergency. I know some of my colleagues think that sounds super dramatic, but as a pigment expert, that’s when we can have the most impact on our patients who have active, unstable disease, really stabilizing that. We’re going to talk in a minute about those stabilizing methods, but I’m glad you mentioned that this 1% concept, this VASI concept, is a validated tool.
Ted Lain, MD: Absolutely.
Seemal Desai, MD: Clinical trials, real life practice. Then why don’t you also, Ted, remind our audience the thumbprint, remember, the patient’s own thumbprint is 0.1%.
Ted Lain, MD: That’s right.
Seemal Desai, MD: And that’s also calculated.
Ted Lain, MD: Great point, Seemal. So, this is 0.1%, this is considered 0.3%, usually like an entire thumb is 0.3%, so that is also a way that we assess the amount of depigmentation or body surface area involved with the vitiligo. Another question you asked me, though, was how we assess whether it’s active. And we already talked about this: whether there’s trichrome vitiligo, or a bit of confetti, or erythema at the border, that is relatively unstable, active vitiligo, and many of the trials require that as well. It could not be a vitiliginous area that has been stable for many years. Some of the trials and the protocols in their inclusion criteria require some degree of activity.
Seemal Desai, MD: Yes, and hold that thought, because we’re going to talk about the data from the trials in a minute. Nada, let me go back to you really quick, because I love when you talk a lot about differential diagnosis, and I intentionally wanted to wait because your active, unstable comment is a good segue to scoring VASI and talking about that. But let’s take one more step back. When you see patients who come in with hypopigmentation, a lot of times I get patients who come in, the parents are frantic, the patients themselves are frantic, “Oh, this is vitiligo.” And it’s not depigmented. You use your Wood lamp, you use your dermoscopy, and we reassure the patient, “It doesn’t look like vitiligo now.” Vitiligo does not become depigmented without going through a hypopigmented phase first. Do you want to talk a bit about how you approach the differential diagnosis of hypopigmented dermatoses?
Nada Elbuluk, MD: Yes, absolutely. To your point, there are a lot of things that can be mistaken for vitiligo. One of the most common, everyday things is something called tinea versicolor, which is a fungal infection that can show up typically on the trunk, back, chest, and it can be medically hypopigmented but to the layperson look like light spots. But they typically have a bit of scale and they’re not completely depigmented, they stay hypopigmented. But sometimes, particularly in our skin of color patients who have darker baseline skin, it can look really light, and it can be alarming to them, especially if it’s been there a long time. Another common condition, seborrheic dermatitis, in our darker skinned patients shows up as hypopigmented. That often can be markedly lighter than their normal skin, and be confused for vitiligo.
There are other conditions that are localized, like a nevus depigmentosus, sometimes initially people think is vitiligo, again, but it’s not. Nevus anemicus is another one. There are more uncommon things like hypopigmented sarcoidosis, hypopigmented mycosis fungoides, rare fungal things like pinta or onchocerciasis, all of those things can show up with depigmentation. There are also other disorders of depigmentation like piebaldism, albinism, scleroderma, when you talk about the salt and pepper presentation. All of those things can also look like vitiligo. The other common one I meant to mention is progressive macular hypomelanosis, which is often on the trunk, and again is hypo, not depigmented, but people can often be worried about vitiligo. There are lots of things in the differential, which is why it’s so important to make sure we rule everything out.
Transcript edited for clarity