DermEd: Recent Episodes

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General: benign epidermal proliferations caused by various papilloma viruses, common wart is called "verruca vulgaris"

Pathogenesis: dsDNA virus infects and replicates in keratinocytes, presence of virus stimulates epidermal thickening, still a lot to be learned!

HPI: child, young adult who is sexually active, skin lesion that can be painful, single or in groups

Risk factors: HPV infection, immunosuppression, meat handlers have higher incidence

Physical exam: papules/nodules that are flesh-colored, with a corrugated (shaped into alternate ridges and grooves) surface, may scale, will have interrupted skin lines with black puncta, often on hands and fingers

Types of warts: flat (slightly raised, flat-surface, well-marginated, often linear from autoinoculation), plantar (bottom of foot, often with callus), genital (condyloma acuminatum, soft/moist, sessile/pedunculated, cauliflower-like appearance, acetowhitening), types 6 and 11 cause genital warts, types 16 and 18 cause cervical cancers

Differential: callus (can use paring to distinguish; after paring warts will show interrupted skin lines with black puncta), carcinomas (ulcerative, refractory), comedones (smooth top), lichen planus (red-purple), corns (normal skin lines with translucent core), condyloma lata (genital syphilis, darkfield microscopy), seborrheic keratosis, Bowenoid papulosis

Histology: biopsy performed when suspicion for carcinoma is high, shows hyperkeratosis, acanthosis (thickened epidermis), within the granular layer will see vacuolated keratinocytes, koilocytes (large keratinocytes with small pyknotic nuclei surrounded by clear cytoplasm), upward extension of dermal papillae with capillaries

Complications: 35-65% resolve spontaneously within 2 years, main concern is carcinoma, types 16/18 highly associated with cervical and anal carcinoma, need to do pap smears in female patients, consider examining the sexual partner of the patient, epidermodysplasia verruciformis = rare disease with diffuse, refractory warts due to HPV-5,8 that convert to squamous cell carcinoma**

Treatment: prevention is key; Gardasil vaccine protects against types 6, 11, 16, 18. Other than prevention, treatment aims to destroy keratinocytes infected with virus and can be quite painful. Treatment options = cryotherapy including 1-2 mm beyond margins + second freeze with follow-up useful for all warts; salicylic acid w occlusive tape for common and plantar warts; cantharidin for children (derived from blister beetle!); Retin-A for flat warts; 25% podophyllin resin for genital warts (toxicity, avoid during pregnancy); alternative treatments include 5-FU, interferon, biologics such as imiquimod

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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General: a benign tumor covered in epithelium with a dermal stalk 

Risk factors: middle-aged

Physical exam: tan or flesh-colored, small, pedunculated papule with a smooth surface, often in regions such as the axilla, groin, neck, eyelids, can have necrotic, crusty appearance if irritated 

Differential: nevi, neurofibromas (can be pressed in), carcinomas 

Histology: thickened epidermis with dermal connective tissue as a stalk, hyperkeratosis, papillomatosis, acanthosis, only need to send necrotic or large tags to lab  

Complications: cosmetic appearance, irritation, # can increase with age

Treatment: none necessary unless troublesome for patient, then (1) snip off with scissors or (2) cryotherapy

Do not attempt to cut off a skin tag with scissors at home on your own! This can be dangerous and lead to bleeding and infection. Please see a dermatologist who can remove the tag safely!

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK 

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General: benign epidermal proliferation

HPI: gradually-appearing lesions later in life, slow-growing, patient may have scratched it off but it recurs

Risk factors: middle-aged adults, family members with similar lesions (autosomal dominant inheritance)

Physical exam: small, elevated, tan, brown, or black "stuck on" papules/plaques with a greasy appearance and well-defined margins, sometimes scaling, pedunculated, verrucous

Differential: actinic keratoses, warts, nevi (dermal growths), melanomas and carcinomas

Histology: can perform excisional or deep shave biopsy to rule out melanoma or carcinoma; you will see hyperkeratosis and pseudocysts (keratin-filled invaginations of the epidermis)

Complications: can become inflamed and form a lichenoid keratosis, can form more lesions with age, Leser-Trelat sign: rapid increase in size and # of seborrheic keratoses along with pruritus can be a sign of malignancy involving the stomach or certain reproductive organs

Treatment: none needed unless troublesome for patient, in that case (1) cryotherapy, (2) curettage

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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General: infection of epidermal cells with poxvirus, most common in children

Pathogenesis: can spread by intimate contact, virus replicates within keratinocytes and forms large bodies in the cytoplasm, center of lesion disintegrates

HPI: pediatric patient with rash, adult with sexual history and genital lesions, patient with HIV/AIDS

Physical exam: smooth, small, flesh-colored, dome-shaped papules with central umbilication, can be single lesions or multiple, can progress to large number of lesions 

Differential: basal cell carcinoma (older patients, telangiectasia), central umbilication is key!

Histology: biopsy usually not necessary, but you can remove papule and crush onto a slide, will see molluscum bodies (sacs containing virions) and thickened epidermis 

Complications: lesions can persist for years or become inflamed, can involve eyes to cause conjunctivitis, dissemination in immunosuppressed patients 

Treatment: (1) spontaneous resolution within months, if not resolving (2) cryotherapy, (3) salicylic acid,  or (4) cantharidin (chemical blistering), goal of treatment if necessary is to destroy the lesion

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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General: areas of friction/pressure that undergo epidermal thickening, very common 

HPI: patients have discomfort with walking or standing, maybe uncomfortable shoes, lots of barefoot walking

Physical exam: thick, brown/yellow or white/gray plaque or nodule, circular, well-circumscribed, horn-like, if one were to scrape the surface it would reveal a clear center with intact skin lines 

Differential: warts (may not have a central clearing with intact skin lines)

Histology: hyperkeratosis, thickened epidermal layer, however biopsy is unnecessary 

Complications: can persist, can get bursitis, infection, and even gangrene in at-risk patients (neurologic dysfunction from diabetes, arteriosclerosis)

Treatment: (1) paring with scalpel, (2) 40% salicylic acid  plaster to soften (keratolytic), (3) correct underlying cause of excessive pressure or friction, can also do surgery if anatomical skeletal deformity exists 

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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General: second most common skin cancer, malignancy of keratinocytes in the epidermis

Pathogenesis: radiation, chemicals (arsenic), occupation exposures (soot, coal, tar), HPV alter cellular genetic material

HPI: chronic skin lesion, not healing, occasionally bleeds or ulcerates

Risk factors: sun/radiation exposure (geographic, occupational), carcinogen exposure, > 60 y/o male, lighter skin pigmentation, family/past medical history of skin cancer,

Physical exam: hard, scaling, indurated, crusted, erythematous to flesh-colored patch/plaque/nodule, may bleed or ulcerate, often on sun-exposed areas (head, neck, arms), near scars or lesions, can involve mucous membranes and lower lip

Differential: keratoacanthoma (rapid growth, central crater of keratin), basal cell carcinoma, seborrheic keratosis, wart, hypertrophic actinic keratosis, SCC in situ on the glans penis = erythroplasia of Queyrat

Histology: hyperkeratosis, abnormal keratinocytes, can invade dermis, can classify via grades 1-4

Complications: can metastasize (increased risk if > 2 cm, high grade, dermal invasion, location on ear/mucous membranes) through lymphatic system, SCC from AK has low risk of metastasis

Treatment: (1) reduce sunlight exposure (hats, long-sleeves, SPF 30 sunscreen, avoid mid-day sun), (2) excision, (3) electrodessication and curettage, (4) Mohs, could also try radiation

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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General: malignancy arising from basal cells of the epidermis, four subtypes (nodular, pigmented, superficial, scarring), most common form of cancer

Pathogenesis: cell in the basal layer of epidermis undergoes mutation causing unregulated growth, can be from insult (UV radiation, arsenic), genetic and involves the hedgehog pathway

HPI: new growth that bleeds, history of skin cancer

Risk factors: sun exposure (geographic location, occupation), light skin pigmentation, lesions on nose or ear have high recurrence rate

Physical exam: sun-damaged skin (freckles, wrinkles) in sun-exposed areas (head, neck), nodular type, most common, presents as pearly, partially translucent papule/nodule with telangiectasia, waxy borders, and a central indention, often on the nose, pigmented type presents as a speckled, blue-black papule/nodule with a pearly margin, superficial type presents as a red, scaling, well-defined patch on the chest, often resembles eczema, can have a depressed center, pearly border, scarring type, most aggressive, presents as a white plaque resembling a scar with some crusting or erosion

Differential: sebaceous hyperplasia (yellow, central pore), nevus, seborrheic keratosis, melanoma, squamous cell carcinoma, dermatitis, look for non-healing and rolled borders, if there's doubt biopsy it!

Histology: uniform, blue-nucleus cells creating a thickened epidermal basal layer with involvement or budding into to the upper dermis

Complications: can become disfiguring, rarely metastasizes

Treatment: (1) reduce sunlight exposure (hats, long-sleeves, SPF 30 sunscreen, avoid mid-day sun), (2) excision, (3) electrodessication and curettage, (4) Mohs, could also try radiation, cryotherapy, topicals like 5-FU

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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General: common precancerous epidermal growths caused by sun exposure

Pathogenesis: UV radiation damages the DNA in keratinocytes, abnormal replication takes place and yields epidermal hyperplasia, dysplasia 

Risk factors: genetics, Caucasian, sun exposure (geographic region, occupation), lighter skin pigmentation

Physical exam: small, rough, scaling, reddish or brownish patch or papule, often on sun-exposed areas like the face, forearms

Differential: seborrheic keratoses (stuck on), carcinomas (larger, well-defined margins)

Histology: partial-thickness dysplasia of the epidermis, hyperkeratosis, parakeratosis 

Complications: indurated or stubborn actinic keratoses should be biopsied to rule out carcinoma, can progress to squamous cell carcinoma 

Treatment: (1) reduce sunlight exposure (hats, long-sleeves, SPF 30 sunscreen, avoid mid-day sun), (2) cryosurgery, could also use (3) topical 5-fluorouracil 5% twice daily for 2-3 weeks for multiple lesions (counsel patients that things will get worse over the next few weeks!)

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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Phototherapy: UVB 290-320, UVA 320-400, can be used to treat skin diseases, such as psoriasis, can cause burns, cancer, and aging

Potassium hydroxide (KOH) mount: can diagnose dermatophyte infection via scraping of the edge of a scaling lesion and placing a drop or two of KOH w dimethylsulfoxide (DMSO) on the slide, blot, examine w low illumination, low power, looking for hyphae, can be difficult to find, can also use to diagnose candidal infection if you see hyphae/pseudohyphae

Tzanck: can diagnose herpetic infection via scrapings from vesicular lesions, can see multinucleated giant cells, for herpetic viral infections can also do immunofluorescent staining

Scabies: can do a scraping of a suspected burrow and visualize the mite

Cultures: scrapings, swabs, biopsies can be sent to assess for bacterial, viral, or fungal growth

Biopsy: punch, shave

Patch tests: used in diagnosing allergic contact dermatitis, patches left on the skin for 2 days

Immunofluorescence: can detect autoantibodies to diagnose blistering disorders

Mohs micrographic surgery: used for basal and squamous cell carcinomas of the skin, layers are removed and examined one at a time to ensure all of the margins of a tumor are removed

Excision: gets tissue sample for study, can remove lesions, length 3x the width, use sutures to close

Electrodessication and curettage: for removal of carcinomas, remove w curette and tx w electrode to destroy remaining cancerous cells

Cryosurgery: uses super cold liquid nitrogen, often used to tx warts or other common lesions such as seborrheic keratoses

With all surgeries and invasive procedures, make sure to get informed consent, discuss complications (neural damage, scarring, infection), discuss alternatives, and educate your patient on their condition!

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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General principles:

• Vehicle (creams, lotions, oils, ointments, solutions, sprays, gels, foams, ointment can be higher potency than cream), concentration, amount, location, directions, expense, insurance, patient preference, generic versus brand name

• Topical therapy: directly to target, less systemic effects, difficult to apply

• Patient's palm ~1% of their total body surface area, one fingertip unit ~500 mg used to tx 2% body surface area, thus two palms ~500 mg, takes ~30 grams to cover adult body, ~2 g for face or hands, ~3 g for an arm, ~4 g for a leg, rule of 9's

• Characteristics of a prescription: generic/medication name, vehicle, concentration, use directions, amount, number of refills

Dressings: protective coverings, dry dressings absorb drainage and can be nonadherent (for clean wounds) or adherent (for debridement/moist wounds), wet dressings treat inflammation, astringent = drying agent, occlusive dressings promote wound healing, baths are wet dressings

Topical steroids: anti-inflammatory, relief for burning or itching, class I (most potent) to class VII (least potent), hydrocortisone 1% ointment and desonide ointment 0.05% are class VI-VII, triamcinolone 1% ointment is class III-V, fluocinonide cream 0.01% is low potency whereas fluocinonide ointment 0.05% is high potency, clobetasol ointment 0.05% is super high potency class I, class determines strength not percentage, class I best for severe scalp, palm, soles, thick lesions, class II-V best for mild-moderate, class VI-VII best for thin skin (face, genitals), intertriginous and large areas, side effects include acne, atrophy, striae, hypopigmentation, telangiectasias, dermatitis, rarely systemic effects such as Cushing's, HPA suppression, glaucoma, for duration use high potency ones for < 4 wks, medium potency < 6-8 wks, low potency in 1-2 wk intervals, when discontinuing treatment make sure to taper, be cautious of thin skin, pediatric patients have different body surface areas, use creams on weeping lesions, ointments for dry lesions, and gels or solutions on hairy areas, tachyphylaxis

Antibacterials: oral cephalexin for cellulitis, topical clindamycin for acne

Antifungals: clotrimazole for tinea infections (except for tinea capitis, use griseofulvin or terbinafine)

Antivirals: acyclovir for herpes

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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Starts with typical patient workup: chief complaint, HPI, PMH, meds, allergies, FH, SH, ROS, PE

HPI: timing, pain, itching, where on the body, how it has evolved, alleviating or aggravating factors, interventions, have they experienced it before, look for atopic triad, ask about any exposures, medications

FH: ask about any family history of the disease or skin cancer

The skin exam:

• Covers the skin, hair, nails, and mucous membranes

• Looking for harmful or dangerous skin lesions, other findings that can help with the chief complaint

• Setup: good lighting (natural, windows), patient undressed in a gown (respect patient's privacy!), measuring tape or ruler, form of magnification, chaperone, sanitize

• Use a systematic approach: examine face, eyes, lips, oral cavity, ears, scalp, neck (including both anterior and posterior inspection), arms, axilla, palms, fingernails, ask patient to stand, examine chest, abdomen, genitalia, back, buttocks ( including perianal area), anterior and posterior legs, feet (dorsum, plantar, toes and toenails), *always ask permission before examining the breasts or genitalia!*

• Use palpation to characterize texture, temperature, consistency

• For non-derm patients, you can still examine the skin by incorporating inspection/palpation into your normal physical exam

• For pediatric patients, try using distraction or having them sit on parent's lap

Taking a picture of an evolving skin lesion for the patient's chart is helpful!

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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Acne vulgaris:

General: results from clogged pilosebaceous units (comedones), forms pustules, papules, nodules, and comedones (open v. closed), commonly affects adolescents, family history is important, affects face, neck, and upper trunk/arms, psychosocial effects

Pathogenesis: androgens increase sebum production, sebum and keratin clog the pilosebaceous unit to form a comedo, bacteria (cutibacterium/propionibacterium acnes) grow and cause inflammatory response, certain medications (steroids, testosterone), tight clothing/pressure on the skin

Classification: comedonal, inflammatory (papulopustular), nodulocystic, mild or severe depending on extent of acne, scarring

Complications: post-inflammatory hyperpigmentation, scarring

Treatments: can take 2-3 months to see effect, adherence is key, using a daily ceramide-containing moisturizer can help

• Topical retinoids: vitamin A derivative, normalizes differentiation of epithelial cells, prevents new comedones from forming, promotes clearing of comedones, can cause dryness, itching, redness, scaling, sensitive skin (use sunscreen!), available as adapalene, tretinoin creams, lotions, solutions, avoid use during pregnancy

• Benzoyl peroxide: kills bacteria via free radical production, available as creams, lotions, washes, can cause bleaching and irritation

• Topical retinoid at bedtime, benzoyl peroxide wash in the morning

• Antibiotics: topical erythromycin 2%, topical clindamycin 1%, can be irritating and can cause dry skin, often prescribed w benzoyl peroxide to prevent resistance, oral antibiotics (tetracycline, macrolides) can be used for moderate to severe inflammatory acne but make sure to consider side effect profiles and patient's age/pregnancy status

• Oral isotretinoin: retinoic acid derivative, used for severe acne unresponsive to other treatments, can cause dry skin and lips, elevated LFTs and triglycerides, teratogenic

• For mild acne, use topical retinoid or benzoyl peroxide, for moderate acne use combo therapy of retinoid and benzoyl peroxide plus a topical antibiotic, for severe acne add oral antibiotic

• For comedonal acne use topical retinoids, for inflammatory/papulopustular acne start w retinoids/benzoyl peroxide then add topical antibiotics for moderate and oral antibiotics for severe, for nodulocystic acne use topical retinoid/benzoyl with topical antibiotic, do oral antibiotic if severe, oral isotretinoin if unresponsive, can use adapalene for sensitive skin

• For pediatric patients, consider underlying systemic problems, avoid tetracyclines in patients with age < 8

• Spironolactone and OCPs can treat acne via decreasing amount of androgens

Avoid over-the-counter products, harsh scrubs, excessive washing

Diet can contribute; low-glycemic carbs are good, chocolate and greasy foods do not have significant effect on acne

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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Terminology for morphology: macule, patch, papule, plaque, vesicle, bulla, pustule, nodule, cyst, crust, scale, lichenification, erosion, ulcer, wheal

Approach to rashses:

Step 1: describe morphology.

Step 2: describe distribution and configuration.

Step 3: consider which skin layers are involved.

Step 4: apply information to clinical context and story.

Examples: flat or raised, size, color, shape, texture, configuration, distribution

References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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Components of the skin: epidermis, dermis, subcutaneous, appendages

Functions of the skin: barrier, sensation, temperature regulation

Epidermis: keratinocytes, layers (basal, stratum spinosum, stratum granulosum, stratum corneum), regenerative cells in basal, desmosome junctions in spinosum, keratohyalin/lamellar granules in granulosum, melanocytes contain melanosomes, Langerhan's cells, basement membrane zone

Dermis: contains blood vessels, nerves, collagen, elastin, matrix, appendages

Subcutaneous: fat  tissues, insulation, energy source, protection

Appendages: eccrine glands (cholinergic sweat), apocrine glands (androgen-dependent), sebaceous glands (sebum), hair follicles, nails

References:  AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK

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Welcome to the DermEd podcast!

In this episode:

Introduction, purpose, vision, and goals for the podcast

Disclaimer

Email: dermedpodcast@gmail.com