• Liquid nitrogen Dermatologic Procedures • Intralesional steroids • Unna Boots Toby Maurer, MD • Biopsies-snip, shave, punch University of California, San Francisco • …..scabies prep and KOH preps Liquid Nitrogen The Gun vs. The Q-Tip • Thaw time is key • Cost: • Thawing destroys the cells • Gun delivers more constant pressure • Freeze to get sustained ice ball & adequate thaw time • Gun is faster if you have the volume • Thaw time - From time the lesion is white until it goes back to normal color • Always do 2 cycles of thawing 1
Liquid Nitrogen (cont’d) Know what you are freezing • Thaw times differ by location – Face/genital 2 x 15 sec. thaws and dorsal arms • Check that pt has resoltuion of lesion- document that you told them or that you are – Palms/soles 2 x 30-45 sec. thaws bring them back • Thaw times differ by diagnosis – Seborrheic keratoses - 15 sec. thaws – Actinic keratoses - 15 sec. thaws – Warts - need more & want to go 1mm around periphery Side Effects Intralesional Steroids • So cold it feels like a burn • Used for keloids, hypertrophic scars, patches of alopecia areata • Blister tonight then crust that will take 5 days to resolve (15 sec. thaws) vs. 10 days • Trick is not to go into fat but stay in dermis(don’t want atrophy) (30-45 sec. thaws) • Warn patient and document potential side effects • Can break the blister like pigment change and atrophy • Warn re: hypo/hyperpigmentation in • For alopecia areata -10 mg/cc; 1-3 cc per month persons w/underlying pigment • For Keloids-20-40 mg/cc; 1 cc per month 2
Keloids How to do a KOH • Intralesional steroids-20-40 mg/cc • Scrape the area and GET LOTS of scale-use a 15 scalpel • Pts will absorb steroids systemically so limit is 40 mg per month • Place cover slip on top of scale • Anaesthetize surface with lidocaine and • Put a drop of KOH on the side of the cover epinephrine using 30 gauge needle slip and let it go under the slip by osmosis • Get into the right space and inject steroid with 22 gauge needle • Heat the specimen not to point of boiling (Important to do when you have dry skin) • Use your pen to put pressure on cover slip to separate the cells • Bring your condensor all the way down • Use 4x power and MAX of 10 x power to look for hyphae 3
Scabies Prep • Why do it? Not everything that itches is scabies Tip : itchy nodules on penis=scabies • Don’t rely on finding a burrow but if you do, scrape it-high yield • Highest yield areas-between the fingers, wrists, scapula, lateral edge of the feet-look for papulovesicular lesions that are primary (not scratched) 4
Juice and scale go on slide, place cover slip on top Mineral oil is great but water will do Bring condenser all the way up Look at every part of slide and especially around cover slip edges Unna Boots • For venous ulcers when there is edema • Make sure there is no cellulitis before you cover an area • You will need: Currette, +/- lidocaine (no epi), metrogel, duoderm, allevyn, unna boot 5
Unna Boots • Never too tight • Leave folds in place • Anchor joints • Start at mid foot and work up to the knee • Coban layer on outside • If pt notes pain, take dressing off 6
Biopsy Tips BIOPSIES • Give your pathologist an adequate and representative sample • Pathologists are only as good as the clinician • Choose a lesion that has not yet evolved • REFER - If you have no idea what you are • Don’t crush the tissue looking at, neither will the pathologist. • If your results don’t make sense, call the • Must include history, location and pathologist or a dermatologist for review DIFFERENTIAL diagnosis-what are you • Billing: procedural code for biopsy (including ruling out AT LEAST closure)-neoplasm of uncertain behavior 7
Informed Consent • NUMBING IS STANDARD OF CARE • 1% Lidocaine and epinephrine • Why are you doing this? • Epi-okay to use on fingers, toes, and penis unless using large doses • What could be done instead? • Do not use Epi in Reynauds or other vascular problems • Risks involved (lower leg vascular insufficiency) • EMLA in Kids followed by IL numbing – Scar • Lidocaine allergy – Infection • IL Benadryl – Bleeding Snip Biopsies/Excision Shave Biopsies • Scissor snip • Leave half of lesion behind so you know to where to return for definitive treatment • Skin tags • Puff up section with anesthetic and • AlCl for hemostasis LIGHTLY pick up with forceps-scalpel cuts • Send to pathology under skin • Al Cl for hemostasis • Do NOT use silver nitrate or Monsels on visible skin • Petroleum jelly/bandaid 8
Punch Biopsies Punch Biopsy • Allows you to get to the top of the fat • Punch (sizes 2-6mm) • You will get the epidermis and dermis – 2mm - Not enough info for pathologist • Use for diseases that go into the dermis from the epidermis or that originate in the dermis. (Hint: – 3 mm - Use in cosmetically sensitive areas There is a palpable or papular/ nodular – 4mm - Standard component.) – 5-6mm - Use to get around lesion or if submitting part of a biopsy for tissue culture 9
Punch Biopsy - You Will Need How to make a hole oval? • Non-absorbable suture • All in skin tension lines – 2mm & 3mm - one stitch – 4mm - two stitches – 5mm and 6mm - three stitches – GELFOAM Excisional Biopsies Suturing • You have control • Interrupted adequate • Go down to fat, through fat to fascia & beyond • Double knot for first throw then 3 more • Lets you get around the lesion entirely single knot throws – Malignant melanoma • Remove sutures in 3 days face, 7 days back, – r/o Dysplastic nevus vs. malignant melanoma chest and 10-14 days limbs – Vasculitis – Panniculitis • Petroleum jelly/bandaid-keep wound dry – Epidermoid cysts 10
• Mark it with pen before putting in anesthetic • 3:1 rule-measure lesion- If 1 cm, then will need total length to be 3 cm (1.5 cm on each side) for proper closure 3 cm 1 cm 11
• Don’t bevel blade-should be perpendicular • Undermine edges for larger wounds-helps to close 12
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