Botulinum Toxin Injection

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Complete Reflection


Our next model here is Molly. Molly suffers from axillary hyperhidrosis or excessive sweating and she’s seeking some botulinum toxin treatment to help her with this. You’ll notice that we’ve just cleaned the axillary area here and although I’ve just wiped it dry, we can already see small beads of perspiration appearing almost instantaneously. Now in some patients like Molly, where the sweating is very obvious, we can just go ahead and treat, but in other patients in whom we need to diagnose exactly where the sweating is coming from and see if they truly have hyperhidrosis, we can perform the starch iodine test. To do this, we first apply some iodine to the axillary area. When you’re performing this test, try to avoid using iodine that’s in an alcoholic base. Take the iodine and dip it in some gauze and then you can wipe the axilla with the iodine. Try to get all the hair-bearing area because this is typically where the sweat glands are concentrated. We apply an even amount of the iodine and then we wipe off the excess so that the area is not too wet.


After wiping away the excess iodine, you next take some cornflour which you can get from any grocery store and apply a light layer of the cornflour using a little makeup brush. You will notice that in Molly there’s almost an instant reaction between the cornflour, the iodine, and the perspiration that creates a black discolouration. In some patients, you may have to wait a considerable time to see this, but in Molly, we can see it almost instantaneously.

Injection Markings

When we review Molly following the starch iodine test we can see that we have a line of excess sweating as shown by the black discolouration. Accordingly, I will make a grid to guide our injections. I remove the excess starch iodine and I will mark out a rectangle within which to draw our grid.


Using a marker and taking into account the field that I want to get inject in, I draw out a rectangle. I want to use approximately half a syringe per axilla so that will be 50 units in total. Therefore, I will make a grid which is 4 by 6 squares giving me a total of 24 squares, and if I inject two units into each one of these squares that will be a total of 48 units of botox per side.


We will now proceed to treat Molly for her hyperhidrosis. I now have my 1 ml syringe with a 32 gauge needle. You will notice that the orientation of the syringe and needle is very flat, and this allows me to inject in a very superficial plane. The ideal depth of injection here is intradermal. Remember that we are targeting the sweat glands, and the sweat glands are a dermal structure. Accordingly, we want to maintain a depth which is as superficial as possible in the intradermal region. Sometimes you will see, particularly in patients who have thinner skin, you may notice a small bleb as you inject, and this is absolutely fine.


Because Molly has thicker skin, we are not really seeing the intradermal blebs. Remember, each injection is 2 units, and I am injecting a quantity of 0.1 ccs into each square. After I finish with the first syringe I will move on to the second syringe, and you will notice that in total I will inject 48 units. Some patients who are either bigger or who have a wider pattern of sweating may require additional toxin treatment, perhaps going up to 75 or 100 units per side. I have found that by using a 32 gauge needle, we can keep the treatment very comfortable; patients were often complaining of discomfort with a 30 gauge, but 32 gauge seems to be much better in my experience.


You will notice that as I finish the second syringe I will then have four squares remaining to treat with the third syringe, so at the end, I will have an additional 2 units which I can inject anywhere within my grid. As I mentioned in the marking up video, if you want to omit the starch iodine test, you can just create your grid in the hair-bearing area of the axilla, as this is the area most likely to produce the excess sweating, and as I mentioned I have an extra 2 units which I can just inject anywhere within the grid.