What does skin biopsy reveal in lab tests?

October 21, 2014 1:58 PM

Hi MeFi, I've asked about skin issues before sometime last year and I still haven't found what it could be. My dermatologist said that I have become immune/resistant to topical treatments (benzyl perox, clindamycin, clindamycin, erythromycin) and that he needed to take a sample and conduct a skin biopsy. On a first whim, he said I likely have 'Folliculitis' but he's not sure since my skin didn't respond to topical treatments. So today he did a skin sample and I'm just curious to what exactly do lab-results show when it comes to skin biopsy. Do they look for certain bacteria or do they get an overall result of what has been in my body as far as food, drugs, liquids go? All I really use 'recreationally' is marijuana through a vaporizer to treat my neck pain but this dermatologist is sorta ultra-conservative and a friend of the family so I'd hate have to explain stupid things to him should they even come up during the test results. TL;dr - Do Skin Biopsy lab results show drug use or just skin bacteria? Thanks everyone!
posted by bostonhill to Health & Fitness (6 answers total)

Best answer: Usually a biopsy is just an examination under a microscope. They will look at the shapes and content of the cells to differentiate bacteria, fungus, healthy skin, or even cancer. They won't be able to tell what you've been eating, drinking, or consuming.
posted by muddgirl at 2:07 PM on October 21, 2014 [2 favorites]

Best answer: There will be no drug/substance testing of your skin biopsy at all.
posted by quince at 2:12 PM on October 21, 2014 [1 favorite]

Response by poster: Thanks @guince & @muddgirl!
posted by bostonhill at 2:33 PM on October 21, 2014

My skin biopsy looked at neutrophils and other -phils.
posted by vitabellosi at 3:16 PM on October 21, 2014

In my personal experience my derm did a skin biopsy to get an up-close view of what was going on.
posted by radioamy at 3:23 PM on October 21, 2014

Best answer: In this case, they'll be fixing the tissue, cutting it into thin slices, staining with chemicals and then sending to a pathologist to examine under a microscope. The diagnostic power of pathology cannot be over-stated. It is really amazing how much information can be found in a single sliver of tissue less than 5 millionths of a meter in thickness.

In some cases, skin biospies may be assessed for genetic changes by polymerase chain reaction, but that's only when certain types of neoplasm are suspected.
posted by kisch mokusch at 3:44 PM on October 21, 2014 [1 favorite]