Removing patches
Before removing patches, it is essential you check your chart compared to what is actually on the patients’ back. Check that the numbers and the direction of the patches match what is documented on the chart. If any mistakes have been made, this is the last opportunity to identify them. At SHI, before any patches are moved, a photograph is taken with patches still insitu. A photograph is then taken with the patches removed. This is vital in following up late reactions.
After numbers have been checked, remark the purple lines with a skin marker next to the discs so they will still be identifiable (Figure 1) and show the doctors where the patches were originally positioned for the final appointment.
| Figure 1 – Example of remarking patches Once the purple lines have been remarked, the patches can be removed. The removal of the patches can be uncomfortable for some patients and it is important to ask the patient if they prefer a fast or slow removal of patches. If extra tape such as Micropore™ has been applied over the top, remove this first. Wipe over the patients back with gauze to remove any excess allergen. |
Once patches are removed, place thin pieces of tape on the top of the patch location and write numbers on the tape with permanent marker, or numbers can be written directly on the skin with a skin marker (Figure 1 & 2).
If you don’t feel confident writing the numbers after all patches are removed, number them as you remove the patches (Figure 2). This may be useful if the patches have been applied in an unusual way, if they have been accidentally applied upside down or out of order, or even if you are new to patch testing and get confused with the numbering system. Figure 2 – Example of numbering allergens after patch removal |  |
If patches have been put on horizontally be sure to mark clearly the TOP of the patch, or place the tapes at the top or write the number on the skin to indicate the top (as shown in figure 2).
It is important to remind the patient they should not scratch their back after the removal of tests.
Once patches have been removed, document what time the patches were removed. This is because after patches are removed, the patient must wait for at least 10 minutes before having their patches read by the dermatologist (they are looking for any red, raised itchy spots about the size of a 5-cent piece, and appear where the patches were placed).
When the patches are “read” by the dermatologist, they look for results and interpret the meaning of each reaction (Figure 3). The patient should be reminded they still cannot get the patch area wet until the final appointment (or shower without getting the back wet).
Figure 3 – Example of a positive patch test reaction
On the “patches off” day, occasionally additional patches are added, particularly if a patch hasn’t stuck as well or new products need to be tested (e.g. the patient forgot to bring their own products to the first appointment).
Some patients require their sunscreen patches to be exposed to UVA light on the second appointment. If this is needed, the patches are removed as per normal, including the sunscreen separates located on the patients’ forearm. These should be labelled (with writing on the skin or with thin Micropore™) as ‘UV S/Seps’ to note they are the sunscreen allergens that need UVA light exposure.
A note on the patients chart also appears on the tops right hand corner of the chart with the message ‘UVA 5 joules day 2’, as a reminder (Figure 4). After the UVA light treatment the patient sees the dermatologist as per normal.
Figure 4 – An example of chart with a reminder of UVA
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