a. What is Wood’s light examination?
b. What is it used for?
- 1. Low intensity UV light; fungal infections tend to fluoresce; epidermal pigmentation is accentuated
- 2. Aids in diagnosis of tinea capitis, erythrasma, and porphyria cutanea tarda
Tell me about KOH prep
Drops of potassium hydroxide solution on slide with scrapings. Gentle heating over alcohol burner dissolves keratin, which reveals fungal elements when viewed under microscope
What is indirect lighting technique?
Sidelighting across a lesion in a darkened exam room; even slightly elevated lesions will cast a shadow
What is Diascopy?
- A glass slide is pressed against a lesion.
- Blood-filled lesions (e.g. erythema or hemangioma) will blanch, while purpura (e.g. vasculitis) will not.
What the heezy is a Tzanck smear?
- A smear looking for Tzanck cells, aka multinucleated giant cells.
- Can be found in: HSV, Varicela and zoster, CMV
Curette biopsy techniques
- loop-shaped knife is used to scrape a lesion after local anesthesia
- does not allow study of entire lesion and surrounding tissue
- may also be combined with electrocautery for definitive
- treatment of some lesions, e.g. basal cell carcinomas
- For diagnosing superficial lesions
- Causes less scarring than other techniques, thus often used for superficial facial lesions.
- Circular “cookie cutter” instruments of various diameters are used to cut out a cylindrical core of tissue from a lesion
- Indicated for sampling a portion of lesion; not indicated for suspected malignant melanoma
- Ideal for diagnostic skin biopsy or removing small lesions
Fusiform or elliptical scalpel excision
- Indicated for deep lesions, fragile lesions, and suspected malignant melanoma, where removal of lesion in its entirety lowers risk of spread
- Orient the excision along natural skin creases
- After local anesthesia, excision is performed, with length-to-width ratio about 3:1
- Depth of excision sufficient to see SQ fat when sample removed
- Skin is closed with sutures
What is Moh's microsurgery?
Why do we do it?
- Indicated when:
- - Biopsy of single area tumor
- - Conventional excision would sacrifice too much normal tissue in a cosmetically or functionally critical area (eyelids, nose, ear)
- - Area with high risk of recurrence (temple, scalp, medial canthus, periauricular, perinasal)
- - In general, very effective tx for basal cell or squamous cell Ca
Tell me about Acetowhitening
- Gauze soaked in 5% acetic acid is applied to penis or to
- Subclinical warts (HPV) can then be visualized as tiny white papules on magnification or colposcopy
- Tissue destruction by freezing with liquid nitrogen
- For treatment of benign lesions and occasionally for small, well-defined basal cell or squamous cell carcinomas
- Contraindications: abnormal reaction to cold (cryoglobulinemia, cold urticaria, Raynaud’s disease)
What is Electrosurgery?
- After local anesthesia, electrode is applied to lesion to produce tissue destruction
- Used for warts, skin tags, and other benign lesions
- For basal cell carcinoma, the lesion is first curetted until all abnormal soft tissue is removed, then electrocaudary is used.
How do we use Radiation therapy for skin stuff?
- Indicated for well-defined squamous cell carcinoma and basal cell carcinoma, in older individuals or with involvement of areas such as the nose and ears, where surgery might cause disfigurement.
- Some Ca risk
Laser therapy? whhaaaa?
- Argon laser or tunable dye laser
- Treats Port-wine stain, spider angiomata, cherry angiomata
Talk to yourself about Chemical peels.
- Application of phenol or other irritants to produce inflammation and sloughing of epidermis.
- Sometimes used for unusually severe facial actinic keratosis; or for cosmetic treatment of wrinkles