• 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
Liquid Nitrogen (cont’d) • Thaw times differ by location – Face/genital 2 x 15 sec. thaws and dorsal arms – Palms/soles 2 x 30-45 sec. thaws • Thaw times differ by diagnosis – Seborrheic keratoses - 15 sec. thaws – Actinic keratoses - 15 sec. thaws – Warts - need more & want to go 1mm around periphery
Know what you are freezing • Check that pt has resoltuion of lesion- document that you told them or that you are bring them back Side Effects • So cold it feels like a burn • Blister tonight then crust that will take 5 days to resolve (15 sec. thaws) vs. 10 days (30-45 sec. thaws) • Can break the blister • Warn re: hypo/hyperpigmentation in persons w/underlying pigment
Intralesional Steroids • Used for keloids, hypertrophic scars, patches of alopecia areata • Trick is not to go into fat but stay in dermis(don’t want atrophy) • Warn patient and document potential side effects like pigment change and atrophy • For alopecia areata -10 mg/cc; 1-3 cc per month • For Keloids-20-40 mg/cc; 1 cc per month Keloids • Intralesional steroids-20-40 mg/cc • Pts will absorb steroids systemically so limit is 40 mg per month • Anaesthetize surface with lidocaine and epinephrine using 30 gauge needle • Get into the right space and inject steroid with 22 gauge needle
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 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
BIOPSIES • Pathologists are only as good as the clinician • REFER - If you have no idea what you are looking at, neither will the pathologist. • Must include history, location and DIFFERENTIAL diagnosis-what are you ruling out AT LEAST
Biopsy Tips • NUMBING IS STANDARD OF CARE • Give your pathologist an adequate and • 1% Lidocaine and epinephrine representative sample • Epi-okay to use on fingers, toes, and penis unless using • Choose a lesion that has not yet evolved large doses • Do not use Epi in Reynauds or other vascular problems • Don’t crush the tissue (lower leg vascular insufficiency) • If your results don’t make sense, call the • EMLA in Kids followed by IL numbing pathologist or a dermatologist for review • Lidocaine allergy • Billing: procedural code for biopsy (including • IL Benadryl closure)-neoplasm of uncertain behavior Informed Consent Snip Biopsies/Excision • Why are you doing this? • Scissor snip • What could be done instead? • Skin tags • Risks involved • AlCl for hemostasis – Scar • Send to pathology – Infection • Do NOT use silver nitrate or Monsels on – Bleeding visible skin
Shave Biopsies • Leave half of lesion behind so you know to where to return for definitive treatment • Puff up section with anesthetic and LIGHTLY pick up with forceps-scalpel cuts under skin • Al Cl for hemostasis • Petroleum jelly/bandaid
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 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 • Petroleum jelly/bandaid-keep wound dry – Panniculitis – Epidermoid cysts • 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 • Don’t bevel blade-should be perpendicular • Undermine edges for larger wounds-helps to close
How to do a KOH • Scrape the area and GET LOTS of scale-use • Heat the specimen not to point of boiling a 15 scalpel (Important to do when you have dry skin) • Place cover slip on top of scale • Use your pen to put pressure on cover slip to separate the cells • Put a drop of KOH on the side of the cover slip and let it go under the slip by osmosis • Bring your condensor all the way down • Use 4x power and MAX of 10 x power to look for hyphae
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) 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
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