Family Medicine: Dermatology

Acne Vulgaris

Plugged, inflamed oil glands leading to open comedones, closed comedones, papules, pustules, nodules, or cysts that can scar

-Driven by excess oil, follicular plugging, Cutibacterium acnes, and inflammation

-Dx: clinical, mild has only comedones, moderate has papules and pustules, severe has numerous inflammatory lesions, and cystic has large nodulocystic lesions on face, jaw, and upper body

-Tx: topical retinoid, benzoyl peroxide, topical clindamycin, systemic antibiotic, isotretinoin

Topical Retinoid

What is the treatment of choice for Grade 1 acne?

-Comedones only

Topical Clindamycin

What should be added after topical retinoid and benzoyl peroxide in the treatment of Grade 2 acne?

-Papules and pustules

Doxycycline

What should be added to the treatment of Grade 3 acne?

-Numerous inflammatory lesions, high scarring risk

Isotretinoin

What should be added to the treatment of Grade 4 acne?

-Scarring/refractory

-Contraindicated in pregnancy

Contact Dermatitis

Well-demarcated erythema, erosions, and vesicles after being exposed to an allergen or irritant

-Dx: clinical, patch testing to identify the allergen

-Tx: avoid offending agent, topical steroids

Atopic Dermatitis

Itchy, dry, eczematous patches with lichenification that are classically seen in the flexor creases

-Dx: clinical, serum IgE may be elevated

-Tx: topical corticosteroids and emollients

Seborrheic Dermatitis

Erythematous, yellowish, greasy scale caused by the yeast Malassezia

-Seen most often in the nasolabial folds, eyebrows, scalp, chest; worsened by stress, cold weather, and immunosuppression

-Dx: clinical

-Tx: Ketoconazole shampoo, topical antifungal + low-potency corticosteroid for the face

Perioral Dermatitis

Papulopustular plaques and scale around the mouth that spare the vermillion border

-Dx: clinical

-Tx: topical metronidazole

Drug Eruption

Adverse skin reaction to medicine, usually appearing within the prior 6 weeks

-Presentation: mild, morbilliform rash that clear after stopping the drug ranging to severe life-threatening reactions

-Dx: clinical with careful history

-Tx: withdraw the offending agent, antihistamines

Urticaria

Transient, well-circumscribed, itchy, pink wheals that blanch with pressure and resolve within 24 hours

-Types: acute (IgE mediated), chronic (idiopathic), dermatographism, angioedema

-Dx: clinical with history, CBC, CMP, thyroid function, ANA

-Tx: H1 antihistamines, short course of steroids

Acanthosis Nigricans

Dark, velvety patches in body folds and creases that are usually a sign of insulin resistance

-Most often occurs with obesity, PCOS, and type 2 diabetes

-Dx: clinical

-Tx: treat the underlying condition

Alopecia Areata

Well-demarcated, round patches of baldness from an autoimmune attack on hair follicles

-”exclamation point hairs” are characteristic

-Tx: intralesional corticosteroids, topical minoxidil, JAK inhibitors for severe disease

Tinea Capitis

Fungal scalp infection, causing broken hairs, scaling, and “black dots”

-Tx: oral griseofulvin or terbinafine

Telogen Effluvium

Diffuse shedding after a stressful event that occurred 6-16 weeks earlier

Androgenic Alopecia

Typical male/female pattern baldness, driven by dihydrotestosterone

-Tx: topical minoxidil

Bullous Pemphigoid

Chronic autoimmune blistering disease in which antibodies attack the hemidesmosomes that anchor the epidermis to the dermis, producing a deep, subepidermal split

-Presentation: large, tense bullae and crusts on the axillae, thighs, groin, and abdomen that are more tense, less fragile, and deeper than pemphigus vulgaris. Does not affect mucous membranes, negative Nikolsky sign

-Dx: skin biopsy, direct immunofluorescence shows linear IgG and C3 at basement membrane zone

-Tx: topical or systemic corticosteroids

Erythema Multiforme

Acute, immune-mediated rash with distinctive target lesions on the extremities, usually triggered by an infection (HSV is MC)

-Presentation: 3 zone “target” rash distributed symmetrically on extensor surfaces and palms

-Dx: clinical, skin biopsy if uncertain

-Tx: self-limited, treat underlying cause, valacyclovir suppressive treatment if recurrent and triggered by HSV

Hidradenitis Suppurativa

Chronic disease of follicular occlusion that produces recurrent inflammatory nodules, abscesses, sinus tracts, and scarring

-Presentation: pea to marble sized nodules that enlarge and drain pus where the skin rubs together like armpits, groin, buttocks, and under the breasts

-Dx: clinical, grade with Hurley staging

-Tx: intralesional clindamycin, oral doxycycline for moderate disease, consider adalimumab for moderate-to-severe

Lichen Planus

Chronic inflammatory skin condition characterized by purple, pruritic, polygonal, planar, papules, and plaques that appear on the wrists, ankles, lower back, genitalia, and mouth.

-Associated with hepatitis C infection

-Dx: clinical, confirm with skin biopsy

-Tx: high potency topical corticosteroids

Lichen Simplex Chronicus

“The rash you scratch into existence”

-Presentation: thick, leathery, brownish skin in the posterior neck, wrists, ankles, genitals, or lower legs due to repeated scratching and rubbing

-Dx: clinical

-Tx: break the itch-scratch cycle, high-potency topical corticosteroids

Melasma

“Mask of pregnancy”

-Presentation: acquired hyperpigmentation driven by hormones plus the sun, leading to symmetric brown-gray patches on sun-exposed skin. Seen most often on the face, neck, and forearms

-Dx: clinical

-Tx: sun protection, topical hydroquinone, triple combination cream if refractory

Nummular Eczema

Coin-shaped, oozing, crusted plaques that are intensely itchy

-Common on the lower legs, buttocks, and trunk

-Dx: clinical, KOH to rule out tinea corporis

-Tx: high or ultra high potency topical corticosteroids

Pilonidal Disease

A pit or cyst that traps hair and debris, becoming infected in the natal cleft

-RF: young men, obesity, sedentary jobs, deep natal cleft

-Presentation: midline pit with a secondary abscess or sinus tract and foul-smelling drainage

-Dx: clinical

-Tx: I&D + abx if cellulitis

Pityriasis Rosea

Common, self-limited rash thought to follow reactivation of human herpesvirus 6 and 7

-Presentation: starts with a single “herald patch” and progresses to many smaller “daughter” lesions in a Christmas tree pattern over the course of 2 weeks, also seen along cleavage lines on the trunk. Spares the face, palms, and soles

-Dx: clinical, RPR to exclude secondary syphilis

-Tx: self-limited, oral antihistamines for itch

Seborrheic Keratosis

Benign skin growth in older adults, which is a harmless overgrowth of surface skin cells

-Presentation: brown, waxy, “stuck on” plaques with a well-defined, rough surface. Found on the face, trunk, and extremities. Can be paraneoplastic clue to an internal cancer

-Dx: clinical, shave or punch biopsy

-Tx: none needed

Tinea Versicolor

Scaly, oval hypo- or hyperpigmented macules that do not tan, which is due to the yeast Malassezia furfur

-Location: upper trunk, neck, and proximal arms; common in adolescents and young adults in warm/humid climates

-Dx: KOH prep shows “spaghetti and meatballs” appearance

-Tx: selenium sulfide 2.5%

Vitiligo

Autoimmune condition in which the body destroys its own melanocytes, leaving depigmented patches of skin and hair

-Presentation: well-demarcated chalk-white patches with normal or hyperpigmented borders. Common on the face, hands, wrists, axillae and genitalia

-Common in Hashimoto thyroiditis, Graves disease, T1DM, Addison disease, alopecia areata

-Dx: Wood lamp

-Tx: sun protection, topical corticosteroids, Ruxolitinib cream

Abscess

Walled-off collection of pus in the skin, usually from Staph Aureus

-Presentation: painful, fluctuant, red nodule with surrounding cellulitis

-RF: skin trauma, injection drug use, diabetes, immunocompromise, MRSA contacts

-Dx: clinical, fluctuance is the key finding

-Tx: I&D is definitive + cephalexin / bactrim if MRSA coverage is needed

Cellulitis

Deep bacterial infection of the dermis and subcutaneous tissue with pain, erythema, warmth, and swelling

-Presentation: erythematous, painful, warm swelling of the skin with flat borders and poor demarcation

-Dx: clinical

-Tx: Cephalexin if non-purulent, Bactrim/doxy if purulent

Folliculitis

Inflammation/infection of hair follicles, producing papules and pustules centered on the follicles

-Most often S. aureus, Pseudomonas for hot-tub folliculitis

-Dx: clinical

-Tx: topical mupirocin + benzoyl peroxide

Impetigo

Contagious, crusting skin lesions on the face from S. aureus

-Presentation: sores around the nose and mouth that rupture and ooze, drying into a yellow “honey-colored” crust

-Dx: clinical

-Tx: topical mupirocin, oral cephalexin if extensive

Paronychia

Infection of the nail fold, usually due to S. aureus

-Presentation: sudden pain, redness, swelling, and pus in a patient who bites their nails, sucks their fingers, has hangnails, or got a manicure

-Dx: clinical, culture pus

-Tx: warm soaks + topical mupirocin if without abscess, I&D if with abscess

Intertrigo

Cutaneous candidiasis infection of the skin folds, such as groin and under breasts, that presents as beefy red erythema with satellite pustules and maceration

-Tx: topical azoles +

Thrush

Oral candidiasis presenting as white plaques on the buccal mucosa that scrape off leaving a red base

-Seen in infants, elderly, immunocompromised, inhaled-steroid use

-Tx: nystatin swish-and-swallow for mild, fluconazole for moderate-severe

Diaper Rash

Cutaneous candidiasis presenting as satellite lesions beyond the main rash in a diaper distribution

-Tx: topical creams

Onychomycosis

Fungal infection of the nail

-Presentation: thick, discolored, brittle, crumbling nails with debris under it

-Dx: KOH prep of nail scrapings show branching hyphae

-Tx: oral terbinafine

Tinea Capitis

Tinea infection of the scalp, which is the MC fungal infection in children

-Presentation: broken hairs and scaling

-Tx: griseofulvin PO

Tinea Corporis

Tinea infection of the trunk/extremities

-Presentation: ring with central clearing and a scaly, advancing border

-Tx: topical antifungals

Tinea Pedis

Tinea infection of the feet/toes

-Presentation: itchy-scaling between the toes

-Tx: topical azoles

Hand, Foot, Mouth Disease (HFMD)

Very contagious infection due to Coxsackievirus A16, spread via fecal-oral and respiratory droplets

-Presentation: prodromal symptoms of low grade fever, malaise, and sore mouth for 1-2 days then develop painful oral ulcers, vesicles on the palms/soles/backs of hands and feet

-Dx: clinical

-Tx: supportive, self-limited

Shingles

Reactivation of latent varicella-zoster virus in a sensory ganglion, usually triggered by older age, immunosuppression, or stress

-Presentation: burning/itching/shooting pain along a dermatome for 1-5 days before a grouped vesicular rash develops. Can involve the eye (Zoster ophthalmicus)

-Dx: clinical, PCR if unsure

-Tx: antivirals within 72 hours of rash onset (valacyclovir), Shingrix vaccine if > 50

Measles (Rubeola)

Infection with the contagious, airborne measles morbillivirus

-Presentation: 3-5 days of high fever/cough/conjunctivitis/coryza, Koplik spots on the oral mucosa, then maculopapular rash that begins at the hairline and spreads down

-Dx: clinical, confirm with serum measles IgM or PCR, notify public health

-Tx: Vitamin A for hospitalized children < 2 years old, post-exposure prophylaxis with MMR within 72 hours

Molluscum Contagiosum

Common viral skin infection caused by a poxvirus

-Presentation: smooth, dome-shaped, waxy, flesh-colored papules with a central umbilication that spreads via skin-to-skin contact

-Dx: clinical

-Tx: often self limited (clears in 6-12 months) or use Cantharidin to blister / cryotherapy, Imiquimod if immunocompromised or on the genitals

Rubella

Infection due to the rubella virus, which is spread by respiratory droplets, and prevented by the MMR vaccine

-Presentation: prodromal symptoms of low-grade fever/malaise/LAD (posterior auricular/posterior cervical/suboccipital), pink-red maculopapular rash that starts on the face and spreads downward

-Dx: serum rubella IgM

-Tx: supportive, immune globulin for non-immune pregnant women exposed

Congenital Rubella

First-trimester rubella infection causing deafness, cataracts, cardiac defects, microcephaly, and “blueberry muffin” rash

Varicella

Primary infection with the varicella-zoster virus, which is highly contagious by air and contact

-Presentation: two day prodrome of low grade fever and malaise, pruritic vesicular rash with lesions in different stages of development from the trunk to face and limbs

-Dx: clinical

-Tx: supportive, avoid aspirin in kids, immunocompromised/pregnant adults need acyclovir/valacyclovir

Verrucae

Warts caused by human papillomavirus (HPV)

-Can be seen on the fingers, elbows, knees, face, soles/heels, genitals, eyelids

-Dx: clinical

-Tx: salicylic acid, cryotherapy

Actinic Keratosis

Sun-damage growth that is a precursor to squamous cell carcinoma

-Presentation: flesh-colored, pink, or yellow-brown lesion with a rough sandpaper feel on sun-exposed skin like face, lips, ears, backs of hands, forearms, scalp, and neck

-Dx: clinical

-Tx: cryotherapy, imiquimod

Lipoma

Benign overgrowth of adipocytes

-Presentation: soft, doughy, mobile, painless subcutaneous nodule that is well-circumscribed with normal overlying skin. Common on the upper back, shoulders, neck, abdomen, and arms

-Dx: clinical

-Tx: observe if asx, surgical excision if symptomatic

Melanoma

Malignant tumor of melanocytes, which is the deadliest skin cancer

-RF: UV exposure, fair skin, family history, many nevi

-Dx: ABCDEs, excisional biopsy is gold standard

-Tx: wide local excision, node biopsy if > 1mm thickness

Basal Cell Carcinoma

MC form of skin cancer, which arises from basal cells

-Presentation: pearly papule with raised, rolled borders, telangiectasias, and a central ulcer on a person with fair-skin

-Dx: shave or punch biopsy

-Tx: surgical excision

Squamous Cell Carcinoma

Cancer arising from keratinocytes

-Presentation: firm, scaly or ulcerated papule/nodule on sun-exposed skin that can arise from actinic keratosis, chronic wounds, scars, and mucosa

-Dx: shave or punch biopsy

-Tx: surgical excision with wide margins

Pediculosis

Infestation of parasitic lice, which can affect the head, body, or pubic area

-Dx: visualizing live lice or viable nits on hair shafts

-Tx: Permethrin 1% cream rinse for hair, permethrin for pubic lice

Scabies

Burrowing of Sarcoptes scabiei mites into the epidermis, which is spread by prolonged skin-to-skin contact

-Dx: clinical, skin scraping with mineral oil shows mites/eggs

-Presentation: intense itch especially at night, burrows especially in the finger webs and flexor wrists, and crusts

-Tx: permethrin 5% cream, repeat in one week

Keloid

Excessive scar tissue that grows beyond the original wound, due to dysregulated collagen production

-Presentation: firm, rubbery, raised scar that extends beyond the original wound margins. More common in darker skin tones

-Dx: clinical

-Tx: intralesional corticosteroid injection is first line, silicone gel sheets for prevention, cryotherapy

Epidermal Inclusion Cyst

Benign cyst lined by skin and filled with keratin

-Presentation: smooth, firm, well-circumscribed, mobile cyst with a central punctum. Contents are thick, white-yellow, foul-smelling keratin. Common on the face, scalp, neck, back, and genitalia

-Dx: clinical, US to confirm a cystic structure

-Tx: asx can be observed, elective removal, or I&D if infected

Lyme Disease

Caused by Borrelia burgdorferi, transmitted by the deer tick

-Presentation: starts with erythema migrans, facial nerve palsy, Lyme carditis, meningitis, and arthritis

-Dx: clinical diagnosis if early, serology if late

-Tx: doxycyline

Rocky Mountain Spotted Fever

Infection caused by Rickettsia rickettsii, transmitted by Dermacentor ticks

-Presentation: fever, maculopapular rash that begins on the wrists and ankles and spreads centrally. May become petechial

-Dx: clinical + serology

-Tx: Doxycycline

Abrasion

Superficial wound from friction/scraping that removes the epidermis and sometimes the superficial dermis without full-thickness loss

-Dx: clinical

-Tx: wound irrigation, debridement of devitalized tissue, moist wound healing, tetanus prophylaxis

Black Widow Bite

Spider bite with alpha-latrotoxin venom

-Presentation: causes pinprick pain then severe diffuse muscle cramps (rigid, board-like abdomen), diaphoresis, hypertension

-Dx: clinical

-Tx: opioids + benzos

Brown Recluse Bite

Spider bite with sphingomyelinase D venom

-Presentation: initial painless bite, then a slowly expanding necrotic ulcer

-Tx: wound care, rest, ice, compression, elevation

Superficial

What type of burn is being described?

-Epidermis only

-Dry, red, painful. No blisters

-Heals in 3-5 days

Superficial partial thickness

What type of burn is being described?

-Blisters, moist, pink, and very painful

-Heals in 7-14 days

Deep partial thickness

What type of burn is being described?

-Pale, less painful

-Heals > 21 days with scarring

-May need grafting

Full-thickness

What type of burn is being described?

-Leathery, charred or white/waxy

-Painless

-Requires grafting

Stage 1

What stage of pressure ulcer is being described?

-Intact skin with non-blanchable erythema

Stage 2

What stage of pressure ulcer is being described?

-Partial thickness loss, shallow open ulcer or ruptured blister

Stage 3

What stage of pressure ulcer is being described?

-Full-thickness loss, fat visible, no bone/tendon/muscle exposed

Stage 4

What stage of pressure ulcer is being described?

-Full-thickness with exposed bone, tendon, or muscle

Condyloma Acuminatum

Soft, skin-colored, fleshy growths caused by human papillomavirus types 6 and 11

-Dx: clinical

-Tx: imiquimod if patient applied, TCA therapy in office

Dyshidrosis

Itchy vesicular eruption of clear, deep-seated vesicles without surrounding erythema on the lateral fingers, palms, and soles

-Described as “tapioca pudding” triggered by stress, sweating, contact allergens

-Dx: clinical

-Tx: high potency topical corticosteroids

Erysipelas

Cellulitis with sharply demarcated, raised borders and lymphatic involvement. Almost always due to Group A Strep

-Presentation: looks like cellulitis but is well-demarcated and superficial. Redness, pain, fever, and chills

-Dx: clinical

-Tx: penicillin

Psoriasis

Chronic autoimmune inflammatory skin disease with well-demarcated plaques covered by silver-white scale, classically on extensor surfaces

-Presentation: Auspitz sign (pinpoint bleeding when scale is removed), Koebner phenomenon, associated with psoriatic arthritis

-Dx: clinical

-Tx: topical corticosteroids