Dermatology Diagnostics and Procedures

Patch Test

performed to identify allergens in patients with contact dermatitis, which is a type IV hypersensitivity reaction

-positive results are redness, bumps, papules 48 hours after application

48, 72, 96

Patients undergoing the patch test are checked at __, __, and __ hours

KOH Prep

a test done to detect superficial fungal infections

-high specificity and sensitivity with proper technique

-very cost effective and can be done in office

-indications: scaly annular plaques, areas of scale and or alopecia on scalp, vesicular lesions on feet, thickened nail plates

Chicago Blue

To avoid false positives in the KOH prep, a lab member can use the _______ ___ stain

M. Furfur

What fungus produces a spaghetti and meatball appearance on the KOH prep?

Fungal Culture

performed to determine the presence of dermatophyte fungus

-positive result involves a change in color of medium from yellow to red

Tzank Smear

staining done to detect cutaneous herpes simplex and herpes zoster infections

-reveals multinucleated giant keratinocytes

-significant rates of false positives and false negatives

-indications: presence of vesicles on an erythematous base

PCR

Due to the significant rates of false positives and false negatives with the Tzank Smear, it has been replaced in many settings with ___ testing

Wood’s Lamp

handheld mercury vapor bulb that is most helpful in detecting pigment disorders and certain infections

melanin, darker, porphyrins

The Wood’s Lamp makes lesions with increased ______ in epidermis appear _______ than surrounding skin.

-It’s also used to detect __________ in urine

Dermoscopy

allows for visualization of skin structures in the epidermis and papillary dermis by using a handheld device with 10x lens, LED lighting and polarizing filters

-most commonly used to diagnose: melanocytic lesions, basal and squamous cell carcinomas, and benign tumors

Shave Biopsy

a type of biopsy where layers of the skin are shaved off

-superficial, deep, snip excision, and curettage

Superficial

a type of shave biopsy used for benign, nonmalignant superficial lesions

-warts, keratoses

Curettage

a type of shave biopsy used for benign and superficial lesions

-AVOID IF THERE IS ANY CHANCE OF CANCER

-histologic margins are impossible to determine

Deep Shave

a type of shave biopsy performed when you need to get into the subcutaneous layer

-wide pigmented lesions

Snip Excision

a type of shave biopsy done for acrochordons (skin tags) and pedunculated stalked nevi

Punch Biopsy

used to remove a known lesion or to obtain tissue to assist in the diagnosis of an unknown lesion

-full thickness core of skin that extends to the subcutaneous fat

-a skin punch instrument is used to remove a full thickness cylindrical core of skin

eyelids, penis, excisable

Do NOT perform punch biopsies on the following organs:

-__________, lips, _______

-Suspected malignant lesion if easily _________

Excisional Biopsy

a biopsy that extends to the subcutaneous fat

-incisional: removes a portion of a lesion

-excisional: removal of the entire lesion

bleeding, scarring, drysol, cautery

Biopsy Complications:

-________, infection, regrowth of lesion, ________

-Ways to control bleeding: ________ (20% aluminum chloride solution), ferric subsulfate solution, and silver nitrate ________ stick

Mohs Surgery

a microscopically controlled surgery used to treat common types of cancer like basal cell carcinoma, recurrent tumors, and malignant tumors of the face

stages, pathological, margins

Mohs Surgery Procedure:

-Tissue is removed in a series of _______, with __________ examination of deep and superficial tissue margins after each stage

-Only performed by a dermatologist

Electrosurgery

a procedure that generates sufficient heat to desiccate tissues or achieve hemostasis

-indicated for verruca vulgaris, condyloma acuminata, actinic keratosis, and vaginal lesions

-contraindicated with pacemakers and alcohol based antiseptics

Gram Stain

identifies bacteria in a sample

-very commonly used technique to quickly diagnose bacterial infections

Acne Surgery

opening of the pores of comedones using a comedo extractor to remove the contents within them

-indicated for open and closed comedones