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Dermatology in Primary Care:Recognition and treatment of common disorders

of the skin

Kanade Shinkai, MD PhDProfessor of Clinical Dermatology

University of California, San Francisco

Disclosures

I have no conflicts of interest to disclose.

I may discuss off-label use of treatments for cutaneous disease.

A preview

• Fictional patient

• Series of dermatology visits

• Numerous concerns• Changing mole• Red leg• Drug eruption

“Spots,” skin cancers, melanoma

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Our patient presents with a changing mole

Melanoma

Melanoma

A = asymmetry

B = irregular border

C = color

D = diameter >6mm

E = evolution

complete biopsy

Melanoma: initial evaluation

• Prognosis is DEPENDENT on the depth of lesion (Breslow�s depth)– < 1mm thickness is low risk– > 1mm consider sentinel lymph node

biopsy

D/dx of a pigmented lesion?Seborrheic keratoses

• benign scaly papule• stuck-on tan, ovoid

papule/ plaque• +/- symptoms

Lentigo

• flat, even color• irregular borders• sun-exposed areas:

face, dorsal hands

Pigmented BCC

• pearly papule• prominent

telangiectasias• flecks of pigment

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Common non-melanoma skin cancers

• pearly papule or plaque - central ulceration- telangiectasia

• slow growing

Basal cell carcinoma Squamous cell carcinoma

• scaly pink plaque, nodule• sun-damaged areas• potential for metastasis,

invasion

What is the recommended frequency of skin cancer screening in asymptomatic adults?• USPTF: 2016 update

- insufficient evidence to assess benefits, harms of visual skin exam by a clinician

JAMA 2016; 316(4):429-435Ann Int Med 2009; 150(3):188-193

- Primary care sensitivity 42-100% melanoma- Primary care specificity 70-98% melanoma

Prevention?Let’s talk about photoprotection

Ultraviolet radiation

UVA: 320-400nmPhotoaging, melanomaNot blocked by glass, clouds, ozone

UVB: 290-320nmSunburn, skin cancer, melanomaBlocked by clouds, ozone

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Sunscreen and the UV spectrum

Sunscreen ban 2018: Hawaii bans oxybenzone, octinoxate

Sunscreen versus sunblock

https://www.aad.org/public/spot-skin-cancer/learn-about-skin-cancer/prevent/is-sunsceen-safehttps://www.aad.org/public/spot-skin-cancer/learn-about-skin-cancer/prevent/how-to-select-a-sunscreen

Matta et al (2019) JAMA, 321:2082-2091

Counseling:

SPF 30Broad-spectrum

Nano-technology

Vitamin D

Chemicals -> systemic absorption

Photoprotection

Next clinic visit:The red leg

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D/dx of the red leg?• erysipelas• cellulitis• DVT• vasculitis• pyomyositis• necrotizing fasciitis• asteatotic dermatitis• venous stasis dermatitis• contact dermatitis

Red Leg: Speed rounds

No fever, no leukocytosis, bilateral itchy red legs Stasis dermatitisKey features:

• bilateral erythema, edema (L>>R)• varicose veins• brawny (golden) hyperpigmentation• no WBC, LAD, lymphangitis

Rx: compressiontopical steroids

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Fever, leukocytosis, red leg

• Unilateral• GAS, Staph aureus• Rapid spread• Toxic-appearing patient• WBC up, LAD, streaking

Cellulitis

Fever, leukocytosis, red leg

• Superficial cellulitis (leg, face)• Strep (GAS > GBS)• F>M• Involves lymphatics• Clue: raised, shiny plaques

Erysipelas

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Fever, leukocytosis, minimally �red� legnot responding to antibiotics

Pyomyositis• bacterial infection of muscle

-S aureus (77%), strep (12%)• risk factors:

-trauma-travel (tropics)-immunocompromised

• Dx: MRI• Rx: surgical drainage

psoas, gluteus, quadriceps*

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Necrotizing fasciitis

• Strep/ staph infection of fascia• post-surgical• 20% mortality • pain out of proportion to exam• rapid spread (minutes to hours)• Dx: MRI• Rx: surgical debridement

IV antibiotics

No fever, no leukocytosis, but a red leghistory of topical neomycin for �rash�

Contact dermatitis

• clue: red, angry, weeping, itch>pain• patient looks well• history is key• neomycin is top contact allergen• also: poison oak (rhus)

topical diphenhydramine

Red leg: Pearls

Not all red legs are cellulitis

Bilateral cellulitis is rare. Reconsider diagnosis

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Drug eruptions

Morbilliform drug eruption

• common• erythematous macules, papules (can be confluent)

• pruritus• no systemic symptoms • begins in 1st or 2nd week• treatment:

-D/C med if severe-symptomatic treatment: hydroxyzine, topical steroids

When do the symptoms subside? Up to 1 week

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Drug eruptions: when to worry

Potentially life threateningRequire systemic immunosuppression

Morbilliform drug eruption

Simple

DRESSAGEP

Stevens-Johnson (SJS)Toxic epidermal necrolysis

(TEN)Complex

Minimal systemic symptoms Systemic involvement

Signs of a serious drug eruption:

• Mucosal involvement (ie, oral ulcerations)• Erythroderma• Skin pain• Target lesions• Bullous lesions• Denudation (skin falling off in sheets)• Pustules• Facial swelling, anasarca• Fever• Internal organ involvement: liver, kidney > lung, cardiac

Target lesions: Stevens Johnson Syndrome (SJS) Mucosal involvement: SJS/ TEN

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Bullous lesions, denudation, pain: TENFacial swelling: drug-induced hypersensitivity

syndrome or DRESSAlso: eosinophilia, transaminitis, renal failure

Drug eruption pearlsLook for cutaneous signs of a potentially-fatal drug eruption

Consider ordering labs if you are not sureLab order What you are looking for Drug eruption

CBC with differential Eosinophilia Any drug hypersensitivity(may be slightly

increased in simple drug eruption)

ALT, AST Transaminitis Drug-induced hypersensitivity

syndromeBUN, Cr Acute renal failure Drug-induced

hypersensitivity syndrome, AGEP

Q&A