Dermatology

Editor: Ashley Ciosek, MD
Reviewed by Eva Niklinska, MD

Terminology
Primary Lesions
Term	Definition
Macule	Flat, \< 5mm
Patch	Flat, > 5mm
Papule	Raised, \< 5mm
Plaque	Raised, > 5mm
Vesicle	Fluid filled, \< 5mm
Bullae	Fluid filled, > 5mm
Pustule	Pus filled
Nodule	Firm, thicker, deeper, typically 1-2cm in diameter
Petechial	Non-blanching, \< 4mm
Purpura	Non-blanching, 4-10mm
Secondary Lesions
Term	Definition
Excoriations	Excavations dug into skin secondary to scratching
Lichenification	Roughening of the skin with accentuation of skin markings
Scale	Flakes of stratum corneum
Crust	Rough surface, dried serum, blood, bacteria and cellular debris
Ulceration	Loss of both epidermis and dermis
Erosion	Loss of epidermis

Corticosteroid Potencies:
Low Potency	Medium Potency	High Potency	Very High Potency
Desonide 0.05% (cream, lotion, ointment)	Triamcinolone (Kenalog) 0.1% (ointment, cream)	Betamethasone dipropionate 0.05% (ointment, cream, lotion)	Clobetasol 0.05% (cream, ointment, lotion, gel, foam)
Triamcinolone (Kenalog) 0.025% (ointment, cream)	Hydrocortisone valerate 0.2% (ointment, cream)	Triamcinolone (Kenalog) 0.5% (ointment, cream)
Hydrocortisone acetate (OTC)

Corticosteroids: General Principles

• Main side effects ➔ skin atrophy
• Face and intertriginous areas ➔ low potency steroids ONLY

• High potency steroids should be limited to 3 weeks of use

• Optimal absorption if applied after bathing (hydration promotes steroid penetration)

• Ointments - most potent due to occlusive effect, good for thick, hyperkeratotic lesions and areas of smooth, NON-hairy skin. Avoid hairy and intertriginous areas (can cause skin maceration and folliculitis)
• Creams - more cosmetically appealing and well tolerated. Less potent than ointments
• Lotions - Useful in hairy and intertriginous areas. Less potent than creams

Common Rashes

Morbilliform Drug Rash:

• Description:
• - Erythematous macules ➔ confluent papules
• - Trunk ➔ extremities, symmetric
• - Most common precipitants \= antibiotics (beta-lactam antibiotics, sulfa drugs), allopurinol, AEDs, NSAIDs
• - Sx: Pruritus, low grade fever
• Management
• - Discontinue offending agent
• - Topical Corticosteroids, wet wraps
• - Antihistamines
• - If eosinophilia, kidney/liver dysfunction, mucous membrane lesions or painful/dusky lesions, consider alternative diagnoses (DRESS, AGEP, SJS/TEN)

Erythema Multiforme

• Description:
• - Abrupt onset of papular “target” lesions in symmetrical acrofacial sites, +/-mucosal involvement
• - Usually precipitated by HSV
• - Sx: Lesions can be painful, pruritic or swollen
• - Systemic symptoms likely attributed to inciting infection (HSV, CMV, EBV, flu, COVID, etc)
• Management:
• - Oral antihistamines and/or topical steroids for itch
• - Treat precipitating infections (HSV tx does not alter course of single episode, can help prevent future inf)
• - Stop offending medications
• - If recurrent, derm referral for prolonged antiviral course

Zoster

• Description:
• - Reactivation of VZV leading to blistering, painful rash in dermatomal distribution
• - Rash can last 3-4 weeks
• - Sx: Painful pustular lesions with systemic symptoms including fever, headache and lymphadenopathy
• Management:
• - Best treatment is prevention (shingles vaccine in adults >50)
• - Valacyclovir 1000 mg TID if symptoms started w/in 72 hours and patient has new lesions) for 7 days OR acyclovir 800 mg 5x daily for 7 days
• - Can be complicated by post-herpetic neuralgia, manage w/ early antiviral treatment, topical capsaicin, TCAs, gabapentin/pregabalin

Seborrheic Dermatitis

• Description:
• - Inflammatory response to Malassezia yeasts
• - Characterized by erythematous w/ yellowish and greasy scale of scalp, face, upper trunk, intertriginous areas
• - Can be associated with HIV, Parkinson's disease and use of neuroleptic medications ; consider rescreening everyone for HIV
• - Chronic, relapsing (mildest form \= dandruff)
• - Sx: Usually non-pruritic
• Management:
• - Mild symptoms + isolated to scalp (i.e. dandruff) ➔ antifungal shampoo (Rx: ketoconazole 2%, OTC: selenium sulfide 2.5%)
• - Moderate/severe symptoms w/ scale, inflammation and pruritus of the scalp➔ antifungal shampoo + 2 week high potency topical corticosteroid followed by 2x weekly use of high potency topical steroids

Tinea

• - Pedis - “athlete’s foot”
• - Corporis - body ringworm
• - Capitis - scalp ringworm
• - Cruris - “jock itch”
• - Onychomycosis - fungal nail infection
• Description:
• - Presentation depends on location
• - Pedis: itchy erosions/scales between toes, hyperkeratosis/scale covering soles/sides of feet, vesiculobullous blisters of inner aspect of foot
• - Corporis: solitary circular red patch with raised scaly leading edge, forms ring-shape with hypopigmentation
• - Capitis: partial hair loss, +/- erythema, +/- pustular lesions
• - Curis: erythematous bilateral but asymmetrical rash with raised border and central clearing
• - Onychomycosis
• - Perform KOH preparation if possible to confirm diagnosis
• - Sx: Can be itchy and erythematous or asymptomatic
• Management:
• Treat all sources of tinea to prevent re-infection.
• - Nystatin IS NOT effective treatment
• - Pedis/Corporis/Cruris: if localized infection ok for topical antifungals (clotrimazole 1% BID until clinical resolution 1-4 weeks)
• - Capitis: Oral griseofulvin (500-1000 mg daily for 4-6 weeks) or oral terbinafine (250 mg once daily for 4 to 6 weeks)
• - Onychomycosis: Oral terbinafine (250 mg once daily for 6 weeks (fingernail) or 12 weeks (toenail)), topical therapy (efinaconazole, amorolfine, ciclopirox)

Paronychia

• Description:
• - Inflammation of the skin around a finger or toenail
• - Can be associated with felon (painful abscess at the base of the toe/nail) or herpetic whitlow (viral cutaneous infection caused by HSV)
• - Usually due to staph/strep or pseudomonas
• - Sx: Pain at the site of the infection, can develop systemic infection leading to fever/chills/myalgias
• Management:
• - If no abscess formation, can manage with soaking affected digit in warm water and antiseptics (chlorhexidine soaks TID) with mupirocin applied after soaking
• - If abscess present ➔ I\&D + culture
• - Antibiotics indicated if symptoms not improving after I\&D or systemic symptoms (dicloxacillin 250-500 mg QID, cephalexin 500 mg QID) for 5 day duration
• - If risk factors for MRSA ➔ Bactrim 1-2 DS tablets BID
• - If oral flora present ➔ augmentin 875/125 mg BID

HSV

• Description:
• - Present as clusters of 2-3 mm umbilicated clear or hemorrhagic vesicles persisting for 5-10 days usually preceded by localized tingling/burning
• - Type 1 most commonly associated with oral lesions, Type 2 w/ genital lesions
• - Diagnose with viral culture of swab from vesicle or serologic testing (may be positive and not causing symptoms)
• - Sx: Lesions are painful, can be associated with mild malaise and fever
• Management:
• - No cure, following initial infection immunity develops but does not prevent against further attacks
• - Tx w/ topical therapy for mild infections
• - For initial infection: Valacyclovir 500 mg BID 3-5 d, acyclovir 200 mg 5x/d for 5 days
• - For recurrent infections: oral valacyclovir 500 mg BID for 3 days or 1 g daily for 5 days OR Acyclovir 800 mg BID for 5 days
• - For suppressive therapy: oral valacyclovir 500 mg or 1 g daily

Candida (Balanitis, Intertrigo)

• Description::
• - Balanitis: inflammatory versus infectious condition of the glans penis. Most commonly infectious cause (candida versus dermatophytosis)
• - Sx: penile soreness, dysuria, itchiness, bleeding and erythema of the glans
• - Candidal balanitis associated with white, curd-like exudate
• - Intertrigo: erythematous/macerated plaques with peripheral scaling, often associated with superficial satellite papules or pustules
• - Affects skin below breasts or under abdomen, armpits, groin and web spaces between fingers/toes
• Management:
• - Balanitis: attention to genital hygiene with retraction of foreskin and cleansing for prevention/therapy
• - Clotrimazole cream BID for 7-14 days
• - Intertrigo: Prevention with moisture-free skin, can use talcum powder to assist in intertriginous areas
• - Topical antifungal agents (clotrimazole 1% cream BID for 4 weeks, 1% ointment BID for 2 weeks)
• - Oral fluconazole or itraconazole for severe, generalized and/or refractory cases

Pityriasis versicolor
Pityriasis Rosacea

• Description:
• - Pityriasis versicolor: Superficial fungal skin infection caused by Malassezia
• - Hypo/hyperpigmented or erythematous macules/patches or thin plaques most common on upper trunk, upper extremities
• -Sx: usually asymptomatic
• - Pityriasis rosacea: Self-limiting rash (6-10 weeks) characterized by large circular/oval “herald patch” found on chest/abdomen or back followed by small scaly oval red patches on back and chest (sometimes described in Christmas tree pattern)
• - Sx: vary from mild to severe itching. ⅔ of patients have flu-like symptoms prior to rash onset
• Management:
• - Pityriasis versicolor: Topical antifungal treatment with ketoconazole 2% shampoo (Daily for 3 days), selenium sulfide 2.25% shampoo or terbinafine 1% cream
• - Pityriasis rosacea: Self-limiting disease therefore treatment is symptom management
• - Apply daily moisturizing creams, avoid drying soaps
• - Can trial medium potency topical steroids and oral antihistamines

Atopic dermatitis (eczema)

• Description:
• - Lesions are pruritic, erythematous, +/- weeping/exudative, +/- blistering. Can become lichenified and scaly with fissuring over time.
• - Most commonly occurs on neck, hands and flexural surfaces in adults
• - Associated with atopic triad (asthma, eczema, and allergies)
• Management:
• - Avoid triggers (fabrics, chemicals, humidity, and dryness, foods)
• - Daily skin hydration w/ emollients ointments > creams (take into consideration patient tolerability)
• - Topical corticosteroids: Mild disease - hydrocortisone 2.5% BID until 3-5 d after skin clearance. Moderate disease - triamcinolone 0.1% or 0.025% Clobetasol cream for up to two weeks followed by mild steroids
• - Skin and face folds treatment: Desonide 0.05% OR topical calcineurin inhibitors (tacrolimus 0.1% BID, discontinue when symptoms cleared)

Psoriasis

• Description:
• - Clearly defined red and scaly plaques, symmetrically distributed
• - Most common locations are scalp, elbows, knees
• - Sx: Pruritus is common but mostly mild, treating can lead to hyper/hypopigmented plaques that fade over time
• Management:
• - Limited disease ➔topical corticosteroids and emollients
• - Scalp/external ear canal: potent corticosteroids - clobetasol propionate 0.05% BID until lesions clear
• - Face/intertriginous: low-potency OTC hydrocortisone 1% or prescription-strength 2.5% BID until lesions clear
• - Thick plaques on extensor surfaces: clobetasol propionate 0.05% BID until lesions clear
• - Moderate to Severe ➔ Phototherapy + topical steroids/emollients, before systemic agents (e.g. MTX)

Acne:

• Description:
• - Open and closed comedones, noninflammatory versus inflamed papules/pustules
• - Severe cases involve nodules, pseudocysts with scarring
• Management:
• - sunscreen SPF >=30 daily with broad spectrum coverage
• -Mild acne: daily topical retinoid (tretinoin) + benzoyl peroxide (if papulopustular lesions present)
• - Moderate/severe: Isotretinoin (cumulative dose of 120-150 mg/kg)
• - If isotretinoin is contraindicated, consider oral doxy (100 mg daily for 3-4 m) OR OCP OR spironolactone (25 to 50 mg/day in 1 to 2 divided doses, titrate based on response/tolerability)

Allergic contact dermatitis

• Description:
• - Type of eczema caused by allergic reaction to allergen (type IV hypersensitivity), usually 48-72 hours after exposure
• - Symptoms include erythematous, indurated pruritic plaques, +/- edema, +/- blistering, +/- scale
• - Consider triggers such as nickel, fragrances/perfumes, work exposures, poison ivy
• Management:
• - Determine allergen, if not identified easily, can have comprehensive patch testing
• - Acute/localized rash on hands/feet or nonflexural areas ➔ high potency topical corticosteroids BID until resolution (up to 4 weeks) then taper over 2 weeks
• - Acute/localized rash on face/flexural areas ➔ medium/low potency topical steroids BID for 1-2 weeks then taper over 2 weeks OR topical tacrolimus 0.1% until resolution then taper

Stasis dermatitis

• Description:
• - Caused by venous hypertension resulting from dysfunction of venous valves, obstruction to venous flow
• - Sx: include edema, inflammatory skin changes, pruritus, tenderness, ulceration, varicosity and hyperpigmentation (hemosiderin deposition)
• Management:
• - Compression therapy with bandaging systems or stockings, elevation of legs, regular exercise other than standing
• - Emollient (petroleum jelly) application for dryness/pruritus
• - Acute disease w/ erythema, pruritus, vesiculation, and oozing ➔ consider high/mid-potency topical corticosteroids BID for 1-2 weeks
• - Referral to vascular if persistent symptoms

Rosacea

• Description:
• - Chronic inflammatory condition affecting central face, usually appears between 30-60 yo
• - Persistent facial redness, telangiectasia, thickening of skin and possible development of inflammatory papules/pustules.
• - Pathophysiology multifactorial, includes genetic susceptibility, immune dysregulation, neurocutaneous triggers (sunlight, temperature, exercise, spicy foods, alcohol, stress, tobacco)
• Management:
• - Learn/avoid triggers (alcohol, tobacco), use gentle skin care products, and sun protection
• - Consider pharmacological intervention with topical brimonidine, laser or intense pulsed light therapy
• - If complicated by papular/pustular disease, consider topical metronidazole 0.75% gel for mild disease, and oral tetracycline/doxycycline for moderate to severe disease

Inpatient dermatology

SJS/TEN

• Description:
• - sheet-like skin and mucosal loss
• - SJS \<10% BSA, Overlap 10-30%, TEN >30% BSA
• - incidence: 1-2 affected per million
• - slightly more common in females. 100X more common in HIV
• -most common culprits:
  • -Sulfonamides: cotrimoxazole
  • -Beta-lactam: penicillins, cephalosporins
  • -Anti-convulsants: lamotrigine, carbamazepine, phenytoin, phenobarbitone
  • -Allopurinol
  • -Paracetamol/acetaminophen
  • -Nevirapine (non-nucleoside reverse transcriptase inhibitor
  • -Nonsteroidal anti-inflammatory drugs (NSAIDs) (oxicam type mainly).
  • -usually preceded by flu-like illness: aches, pains, fever, sore throat, conjunctivitis
• -pt typically with marked pain and extremely anxious
• -mortality rate 10% SJS, 30% TEN; can be more accurately predicted with SCORTEN score
• Management:
• -cessation of causative / suspect drugs --consider burns unit admission for wound care management
• -pain management
• -early involvement derm and ophthalmology teams
• -system steroids of unclear efficacy given wound care & infection concerns
• -heated room 30-32degrees
• -consider alternative diagnoses (DRESS, AGEP)

Prickly heat rash

• Description:
• - Heat causes exocrine gland blockage, resulting in raised, itchy rash.
• -associated with former heating pad sites, abundance of blankets
• Management:
• -Take cool baths or showers; tap dry; use cold compresses
• -Wear loose cotton clothing.
• -Use lightweight bedding.
• -Drink plenty of fluid to avoid dehydration.

Leukocytoclastic vasculitis

• Description:
• -inflamed small blood vessels due to infiltration of neutrophils into blood vessel walls
• -rash caused by small areas hemorrhage, resulting in purple red lesions (palpable purpura)
• -punch biopsy to confirm diagnosis
• -frequently occurs in association w/ systemic dx: infection, SLE, RA, Sjogren, malignancy
• Management:
• -early involvement of dermatology: after confirmation via punch biopsy, treat most likely underlying source of disease --tx often involves systemic corticosteroids

DRESS - Drug Reaction with Eosinophilia and Systemic Symptoms

• Description:
• RegiSCAR inclusion criteria for potential cases require at least 3 of the following:
• 1. Hospitalization
• 2. Reaction suspected to be drug-related
• 3. Acute skin rash
• 4. Fever above 38C
• 5. Enlarged lymph nodes at two sites
• 6. Involvement of at least one internal organ
• 7. Blood count abnormalities such as low platelets, raised eosinophils, or abnormal lymphocyte count.--morbilliform drug reaction + erythroderma + facial swelling + mucosal involvement
• -causative agents: allopurinol (esp together with thiazide), sulfa drugs, carbamazepine, phenobarb, phenytoin, iodinated contrast
• -onset \~ 2 weeks of inciting drug
• Management:
• -withdraw all suspected meds --systemic corticosteroids with slow prolonged taper
• -supportive tx with unscented emollients, topical corticosteroids

Pyoderma gangrenosum

• Description:
• -rapidly enlarging, painful ulcer, autoinflammatory etiology
• -full thickness with purple/blue undermined borders
• -50% cases have an underlying disease pathology, ex: IBD (UC>Chron's), RA, leukemia, IgA gammopathy, GPA, Behcet
• Management:
• -mostly non-surgical, though skin grafting may be necessary after active phase
• -potent topical steroid, tacrolimus ointment, oral doxycycline
• -large ulcers may require: oral steroids, anti-TNF (anakinra, infliximab, etanercept) -avoidance of local trauma

Toxic shock syndrome

• Description:
• -pathophys: localized staph infection → bacterial exotoxins trigger massive cytokine release, producing rash (sunburn appearance), fever, hypotension
• -initial phase: diffuse macular rash, "sunburn appearance", fever, multiorgan abnormalities
• -secondary phase: 1-2 wks later: shedding skin in large sheets
• -prior toxic shock sis a risk factor for recurrence
• -majority of cases are surprisingly previously healthy adults aged 20-50
• -complications: ARDS, DIC
• Management:
• -peripheral blood cultures to isolate causative strain. Typically, will use penicillin (or Vanc allergy) + clindamycin

Cutaneous blastomycosis

• Description:
• -skin lesions starting as papules, or pustules. Over course of weeks, develop into ulcerated/crusty sores
• -heal to form raised wart-like scars
• -screen all for HIV
• -when the infection spreads and skin becomes involved, spontaneous resolution does not occur and treatment is necessary.
• Management:
• -treat underlying immunosuppressive condition, for example, HIV
• -ID consult warranted: skin involvement necessitates treatment bc spontaneous resolution does not occur: mild-moderate disease treat with itraconazole, severe disease treat with amphotericin B

RMSF (Rocky Mountain Spotted Fever)

• Description:
• -centripetal rash: begins on hands/wrists, ankles, spreads centrally towards trunk/abdomen. face typically rash-free in beginning of course. Starts as red macules, then becomes papular and petechial
• Management:
• --tx: doxycycline, other tetracyclines. Pregnant females require ID consult.

MIRM (Mycoplasma induced rash and mucositis)

• Description:
• -affects younger demographic than SJS/TEN
• -causative agent \= mycoplasma pneumoniae
• -predominant mucosal & occular features, with fewer cutaneous features than SJS/TEN
• MIRM criteria:
• \<10% BSA with detachment:
• > 2 mucosal sites involved
• Few cutaneous vesiculobullous lesions
• Atypical pneumonia present
• Labs: increase in M. Pneumoniae IgM antibodies, M. Pneumoniae in oropharyngeal or bullae cultures or PCR, and/or serial cold agglutinins
• Management:
• -early Optho and Derm involvement (esp since SJS/TEN should be ruled out):
• -typically, optho will recommend antibiotic drop QID, cyclosporine BID, steroid drops BID, and combo abx / steroid ointment to eyelid margins BID to QID