Testing In Dermatology
Dr. George Woodbury, Board-Certified Dermatologist 12/19/2022
From my perspective of over 30 years of practicing Dermatology, with Rheumatology and Dermatology Associates, Cordova, TN (www.Rheumderm.com. 1-901-753-0168), I have benefitted in my ability to diagnose skin conditions by many advances in testing in Dermatology. Let’s take a look at some of the options for Dermatology testing, used for Diagnosis of skin conditions all the way from Atopic Dermatitis (Eczema) to Contact Dermatitis to pigmented lesions, including types of Skin Cancer and Atypical moles:
First, a helpful test used by Dermatologists is what’s called a Skin Biopsy, meaning taking a lesion, or part of a lesion, off the skin, then sending it into a Dermatopathology Laboratory to be studied. We often first use an injection of local anesthetic called Lidocaine or Bupivacaine to numb up the skin. Then we remove the skin lesion or lesions, at times putting in stitches to speed up the healing of the site or sites. Then the Dermatopathologist stains the cells within the lesion, to look at the pattern of growth, in an attempt to pin down a diagnosis, or certain possibilities of diagnoses.
An essential consideration in taking a biopsy is to consider how helpful this test will be in sorting out the underlieing diagnosis. So the Dermatologist must consider how helpful this test may be, because any time a lesion is removed, a scar will result from the removal, and sometimes a raised and/or painful scar can develop, called a Keloid. Sometimes this Skin Biopsy test can result in nerve damage, including numbness and even loss of ability to move the muscles in the area, and it can increase risks of infection, and sometimes it has to be repeated, if not enough skin cells are removed to pin down the diagnosis.
Sometimes we perform a special type of biopsy called an immunofluorescence biopsy, whereby the Dermatopathologist checks for the presence of autoimmune deposits called antibodies. Sometimes the pattern of these antibodies in the biopsy allows us to better pin down the correct diagnosis, particularly if Lupus or Dermatomyositis are possibilities.
Sometimes we take a brushing from the skin for a test called a KOH or a fungal culture. These tests allow Dermatologists to look for the presence of fungus or yeast in the skin, sometimes by staining of the specimen and sometimes by watching for growth of fungus, growth which can take up to a month. Depending upon which type of fungus is present, we can often discern where this fungus came from, be it from another person, a dog or cat, or the environment.
A helpful type of testing offered by many Dermatologists – including myself at Rheumatology and Dermatology – is Allergy Patch Testing. This type of testing allows me to check for sensitivity to common causes of allergic reactions in the skin, which can include preservatives, fragrances, components of latex, dyes, or certain metals including nickel and cobalt.
Allergy Patch Testing can be either True Testing, looking into a panel of approximately 26 chemicals, or Dormer Testing, also called Extended Allergy Patch Testing, which can include looking into 86 or more different culprit chemicals. At Rheumatology and Dermatology, in Memphis, TN, I use Dormer Testing, a tool which has in many cases allowed me to clarify the cause of patients’ itchy dry long-term rashses.
A couple of rules related to Allergy Patch Testing allow us to get the most helpful results: a.)It is helpful for patients who are having Allergy Patch Testing to come in for 3 visits, generally scheduled on a Monday, Wednesday, and Friday, because we need one appointment to place the test, and follow-up appointments for a standard reading as well as a delayed reading. This scheduling involves three follow-up office visits. b.)It is important to avoid antihistamines such as Benadryl, Zyrtec, and Claritin for at least 72 hours prior to doing Allergy Patch Testing. c.)It is important to avoid swimming and being in the hot tub while this testing is being done, to avoid having the patches that we placed to wash off the skin. It’s also important to avoid profuse sweating while this testing is being placed.
My own Dermatology practice is with Dermatology and Rheumatology Associates, 8143 Walnut Grove Road, Cordova TN 38018 (www.Rheumderm.com, 1-901-753-0168). Or you can find a Dermatologist closer to you by going to the American Academy of Dermatology web site, www.AAD.org, then plugging your zip code into the “Find a Dermatologist” tab.
George Woodbury Jr. M.D. (12/18/2022)