Emergency Medicine Rotation

Emergency Medicine Rotation: Dermatology (PEARLS)

You have completed emergency medicine EOR topics:
Bullous pemphigoid Bullous pemphigoid is a rare, chronic acquired autoimmune subepidermal blistering skin disorder caused by linear deposition of autoantibodies (IgG) against hemidesmosomes in the epidermal-dermal junction

  • Bullous pemphigoid is a less severe than pemphigus vulgarisdoes not affect mucous membranes and has a negative Nikolsky sign
  • Large bullae and crusts located on axillae, thighs, groin, abdomen. More tense, less fragile and deeper than pemphigus vulgaris
  • Diagnosis is made by skin biopsy with direct immunofluorescence exam shows deposition of IgG and C3 basement membrane

Treat with systemic corticosteroids

Bullous Pemphigoid

Bullous Pemphigoid

Lice Pruritic scalp, body or groin. Nits are observed as small white specs on the hair shaft

  • Body (corporis); Pubic (pubis)

DX: Observation of lice and nits; nits = ovoid, grayish-white eggs

TX: launder potential fomites such as sheets in hot water (> 131 F or 55 C)

  • Permethrin topical is the drug of choice used in combination with wet combing
    • Capitis: shampoo to towel-dried hair and wash after 10 minutes then repeat in 9 days
    • Pubis/body lice: permethrin cream apply to entire clean body from the neck down then wash off after 8-12 hours
    • Screen for other STIs in patients with pubic lice - abstain from sexual contact until the infestation clears
  • For eyelash infestation apply ophthalmic-grade petroleum jelly BID x 10 days
  • Lindane = older topical treatment that can’t be used on infants, children, elderly due to neurotoxicity
  • Children OK to return to school after the first application of treatment
  • For resistant cases consider oral ivermectin
  • Treat all family members
Burns Body percentage:

  • Rule of 9’s: Head 9%, Each arm 9%, Chest 9%, Abdomen 9%, Each anterior leg 9%, Each posterior leg 9%, Upper back 9%, Lower back 9%, Genitals 1%
  • Palmar method: Patient’s palm equates to 1%

Degree involvement:

Minor: <10 TBSA adults, <5 TBSA young/old, <2% full thickness, must not involve face, hands, perineum, feet, cross major joints or be circumferential

Major: >25% TBSA adults, >20% TBSA young/old, >10% full-thickness burn, burns involving the face, hands, perineum, feet, cross major joints/circumferential

Treatment: monitor ABCs, fluid repletion, topical antibiotic

  • Cleans with mild soap and water, don’t apply ice directly; irrigate chemical burns with running water x 20 min, topical antibiotic cream to superficial burns, fingers and toes wrapped individually to prevent maceration and gauze placed between them
  • Children with > 10% total body surface area and adults with > 15% need fluid resuscitation ⇒ LR IV x 24 hrs (1/2 in first 8 hrs; ½ in remaining 16)
Pilonidal disease An abnormal skin growth located at the tailbone that contains hair and skin

  • Results from an abscess, sinus tract, at the upper part of the natal (gluteal) cleft
  • Will usually present as a teenager with pain, discomfort and swelling above the anus or near the tailbone that comes and goes
  • Often includes drainage of pus or blood

DX: clinical

TX: drainage and surgical removal of the cyst - look for sinus tract – remove hair, curette granulation tissue

  • Cefazolin + metronidazole or augmentin used empirically with cellulitis
Pilonidal cyst

Pilonidal Cyst

Cellulitis Acute bacterial skin and skin structure infection of the dermis and subcutaneous tissue; characterized by pain, erythema, warmth, and swelling. Margins are flat and not well demarcated.

  • Caused by Staphylococcus and Streptococcus in adults
  • H. influenzae or strep pneumonia in children

DX: culture taken of all purulent wounds and follow up in 48 hours

Treat mild cellulitis (MSSA) with Cephalexin or Dicloxacillin 

  • Cat bite with augmentin or doxycycline if PCN allergic
  • Puncture wound with Cipro (cover pseudomonas)

Treat methicillin-resistant Staphylococcus aureus infection (MRSA) with

  • Trimethoprim-sulfamethoxazole (TMP-SMZ) 1 DS tab PO BID
  • Clindamycin 300–450 mg PO
  • Doxycycline 100 mg PO BID
  • Intravenous Vancomycin or Linezolid
Cellulitis with erythematous tender swelling of the left lower extremity

Cellulitis with erythematous tender swelling of the left lower extremity

Pressure sores Pressure ulcers

Sacrum and hip most often affected, reposition every 2 hours

  • Stage 1: erythema of localized area, usually non-blanching over the bony surface
  • Stage 2: partial loss of dermal layer, resulting in pink ulceration
  • Stage 3: full dermal loss often exposing subcutaneous tissue and fat
  • Stage 4: full-thickness ulceration exposing bone, tendon, or muscle. Osteomyelitis may be present

Wound management by stage of the ulcer

  • Stage I: aggressive preventive measures, thin-film dressings for protection
  • Stage II: occlusive dressing to maintain healing, transparent films, hydrocolloids
  • Stages III-IV: Débridement of necrotic tissue. Exudative ulcers will benefit from absorptive dressings such as calcium alginates, foams, hydrofibers. Dry ulcers require occlusive dressing to maintain moisture, including hydrocolloids, and hydrogels.

Risk factors: age >65, impaired circulation, immobilization, undernutrition, incontinence

DX: based on observation and staged according to classification

TX: debridement ⇒ depends on the extent of necrosis; surgical closure may be necessary; vacuum-assisted closure uses negative pressure to reduce wound edema and remove debris/reduce bacterial load

Pressure ulcer staging. (A) Stage I, erythema; (B) Stage II, breakdown of the dermis; (C) Stage III, full thickness skin breakdown; (D) Stage IV, bone, muscle, and supporting tissue involved.

Pressure ulcer staging. (A) Stage I, erythema; (B) Stage II, breakdown of the dermis; (C) Stage III, full-thickness skin breakdown; (D) Stage IV, bone, muscle, and supporting tissue involved.

Dermatitis (eczema, contact) Acute eczema: rapidly evolving red rash; may be blistered/swollen

Chronic (dermatitis): longstanding irritable area; often darker than surrounding skin, thickened (lichenified) and scratched

1. Contact dermatitis: well-demarcated erythema, erosions, vesicles

  • Allergic:  Nickel, poison ivy, etc. Type 4 hypersensitivity
  • Irritant (diaper rash):  Cleaners, solvents, detergents, urine, feces

Treatment: Avoid the offending agent. Burow's solution (aluminum acetate), topical steroids, zinc oxide (diaper rash)

Contact Dermatitis

Contact Dermatitis

2. Atopic dermatitis: Pruritic, eczematous lesions, xerosis (dry skin), and lichenification (thickening of the skin and an increase in skin markings). Most common on flexor creases (ex. antecubital and popliteal folds)

  • IgE, type 1 hypersensitivity
  • Infant- face, and scalp
  • Adolescent- flexural surfaces
Atopic Dermatitis

Atopic Dermatitis

3. Nummular eczema: Coin-shaped/disc-shaped

Treatment: High or ultra-high potency topical corticosteroids are first-line therapy for nummular eczema

Nummular eczema

Nummular eczema

4. Seborrheic dermatitis (cradle cap): Erythematous, yellowish greasy scales, crusted lesions.

  • Infants- scalp (cradle cap)
  • Adults/adolescents- body folds

Treatment: Ketoconazole shampoo

Seborrheic dermatitis

cradle cap

Seborrheic dermatitis

Adults/adolescents: presents on body folds

5. Perioral dermatitis: Young women. Papulopustular, plaques, and scales around the mouth.

Treatment: Topical metronidazole, avoid steroids

Perioral dermatitis

Perioral dermatitis

Rash Causes

  • Skin rashes can be due to underlying disease
  • Skin rashes can be due to the environment
  • Examples include hot and humid weather, excess sun exposure
  • Other causes include irritating substances and allergies


  • Area of irritated or swollen skin
  • Itchy, red, painful, and irritated
  • It can also lead to blisters or patches of raw skin
  • Rashes can be a symptom of many different medical problems
  • Rashes may basically be divided into two types: infectious or noninfectious

Noninfectious rashes include eczema, contact dermatitis, psoriasis, seborrheic dermatitis, drug eruptions, rosacea, hives (urticaria), dry skin (xerosis), and allergic dermatitis.

Infectious rashes can present with fever

  • For example, the rash in measles is an erythematous, morbilliform, maculopapular rash that begins a few days after the fever starts. It classically starts at the head and spreads downwards.
  • Systemic disease rashes
  • You see with jaundice, CRF, SLE, other autoimmune diseases


  • Differs according to which rash a patient’s diagnose
  • Common rashes can be treated using steroid topical creams such as hydrocortisone or non-steroidal treatments


Rashes are a clue as to what the patient may be exposed to or what infection or systemic disease they may have it is a piece of information that can help to the diagnosis of the patient


Breast/nipple discharge


Other skin conditions

  • Abscess: pain, redness, with or without discharge
Scabies Scabies is a skin infestation caused by a mite known as the Sarcoptes scabiei

  • Pruritic papules ⇒ S-shaped or linear burrows on the skin
  • Often located in web spaces of hands, wrists, waist with severe itching (worse at night)
  • Can’t survive off human >4 days

DX: often clinical, definitive diagnosis ⇒ microscopic observation of mite, egg or feces after skin scrape

TX:  topical permethrin 5% apply to the entire body, wash off after 8-14 hours, THEN ⇒ repeat in 1 week

  • All clothing bedding, towels washed and dried using heat and have no contact with the body for at least 72 hours
  • Oral ivermectin 200 mcg/kg PO once, THEN ⇒ repeat in 2 weeks (take with meals)
    • For adults and children weighing at least 33 pounds who can swallow pills
    • Do not use in pregnant/breastfeeding women
Scabies on the wrist (common site of infection)

Scabies on the wrist (common site of infection)

Drug eruptions An adverse cutaneous reaction in response to the administration of a drug; usually within the past 6 weeks

  • Skin reactions are the most common adverse drug reactions
  • Severity can range from mild eruptions that resolve after the removal of the inciting agent to severe skin damage with multiorgan involvement

DX: clinical – consider bacterial, viral, underlying skin disease like cutaneous lymphoma

TX: monitor for signs of impending cardiovascular collapse (anaphylaxis, DRESS (Drug Rash with Eosinophilia and Systemic Symptoms), SJS/TEN, extensive bullous reactions, generalized erythroderma)

  • Withdraw offending agent
  • Don’t rechallenge with drugs causing urticaria, bullae, angioedema, DRESS, anaphylaxis
  • Anaphylaxis or widespread urticaria ⇒ epinephrine 0.2-0.5mg – prednisone to prevent a recurrence
  • Antihistamines
Drug Reaction

Drug Reaction

Spider bites Brown Recluse: 

  • Brown violin on the abdomen
  • Necrotic woundlocal tissue reaction causes local burning at the site for 3-4 hours → blanched area (due to vasoconstriction) → central necrosis erythematous margin around an ischemic center “red halo” → 24-72 hours after hemorrhagic bullae that undergoes Eschar formation → necrosis
  • TX: wound care, local symptomatic measures, delayed excision

Black Widow:

  • Red hourglass on the abdomen
  • Neurologic manifestations - may not see much at bite site: toxic reaction: nausea, vomiting, HA, fever, syncope, and convulsions
  • TX: wound care, local symptomatic measures, sometimes opioids, benzos; treat with anti-venom in elderly and kids
Erysipelas A distinct form of cellulitis notable for acute, well-demarcated, raised superficial bacterial skin infection with lymphatic involvement almost always caused by Group A strep (strep pyogenes)

  • Symptoms may include redness and pain at the affected site, fevers, and chills

DX: culture and sensitivity


  • Mild disease can be treated with Penicillin G (erythromycin/clindamycin for PCN allergy)
  • Moderate: Bactrim and penicillin/cephalexin
  • severe IMP or MER IV and linezolid BID or Vanco IV/Dapto IV


Erysipelas. This patient has large, confluent erythematous plaques. A bulla is present near the angle of her jaw.

Erysipelas. This patient has large, confluent erythematous plaques. A bulla is present near the angle of her jaw.

Stevens-Johnson syndrome Stevens-Johnson syndrome is a rare, serious hypersensitivity complex that affects the skin and the mucous membranes. It's usually a reaction to a medication or an infection commonly caused by anticonvulsants and sulfa drugs!

  • SJS is 3-10% of the body
  • It begins with a prodrome of flu-like symptoms, followed by a painful red or purplish rash that spreads and blisters. Layers of skin peel away in sheets (+) Nikolsky's sign (pushing blister causes further separation from the dermis)
  • Stevens-Johnson syndrome (SJS) is a milder form of toxic epidermal necrolysis (TEN) with LESS THAN 10% of body surface area detachment

DX: skin biopsy shows necrotic epithelium

DDX: erythema multiforme, viral exanthems, drug rash

TX: stop all offending medications, early admission to burn unit, manage fluid/electrolytes/nutrition, airway stability, eye care

  • IVIG
  • Steroids used to be tx of choice but now thought to increase the risk of sepsis
Stevens Johnson syndrome

Stevens-Johnson syndrome

Herpes zoster Varicella (chickenpox): primary infections - clusters of vesicles on an erythematous base

  • Dewdrops on a rose petal in different stages
  • It starts on the face and spreads down
  • varicella transmitted by respiratory droplets and has 10-20 day incubation period
  • Acutely causes chickenpox - becomes latent in the dorsal root ganglion
  • Symptomatic treatment may use acyclovir in special populations

Herpes zoster (shingles): varicella reactivation causing a maculopapular rash along one dermatome.

  • Identified via tzanck smear with visualization of multinucleated giant cells.
  • Zoster Opthalmicus: shingles involving CCN V, dendritic lesions on slit lamp exam if keratoconjunctivitis is present.
  • Zoster Oticus (Ramsay-Hunt Syndrome): facial nerve (CN VII) otalgia, lesions on the ear, auditory canal, and TM, facial palsy auditory symptoms.
  • Treat shingles with acyclovir, valacyclovir, and famciclovir - given within 72 hours to prevent post-herpetic neuralgia.
  • Postherpetic Neuralgia: pain > 3 months, paresthesias, or decreased sensation. Treat with gabapentin or TCA, topical lidocaine gel, and capsaicin.
  • Recombinant zoster vaccine (RZV, Shingrix) is recommended to prevent shingles in adults 50 years and older
    • Two dose series 2-6 months apart
    • Should be given to patients who previously received Zostavax (ZVL) ⇒ administered at least two months after ZVL
Toxic epidermal necrolysis A rare, life-threatening skin condition that is usually caused by a reaction to drugs

DX: biopsy (necrotic epithelium)

TX: admit to burn unit with supportive care; consult ophthalmology if eyes affected; cyclosporine and possibly plasma exchange for severe cases


Patient will present as → a 5-year-old girl with crusting facial lesions present for 3 days. The mother reports that prior to the development of the facial lesions her daughter was scratching at insect bites. Examination reveals a red facial rash with a golden “honey-colored crust” and pruritus.

A common pediatric bacterial skin infection that is highly contagious and auto-inoculable usually caused by Staphylococcus aureus and Group A beta-hemolytic Streptococci

  • Impetigo typically begins as papules that progress to vesicles and surrounding erythema. Over about one week, the vesicles eventually rupture and form a thick, adherent, golden crust. Regional lymphadenopathy is a common finding.
  • MC seen in children ages 2-5 years
  • The main symptom is red sores that form around the nose and mouth. The sores rupture, ooze for a few days, then form a yellow-brown crust
  • They are nonpainful and pruritic ⇒ “honey-colored” and weeping
  • Most commonly caused by S. aureus
  • Risk factors for impetigo include warm, humid conditions, poverty, crowding, and poor hygiene
    • Secondary impetigo can occur at sites of minor abrasion or scratches

DX: Gram stain and culture is recommended to determine bacterial etiology

Treatment is topical mupirocin, dicloxacillin, cephalexin for more severe illness

  • Patients with suspected or confirmed methicillin-resistant aureus should be treated with doxycycline, clindamycin, or trimethoprim-sulfamethoxazole
  • Antibiotic treatment is usually for seven days
  • Children may return to school 24 hours after starting antibiotics
  • Complications: poststreptococcal glomerulonephritis
Urticaria Urticaria (hives) is a skin rash triggered by a reaction to certain foods, medications, stress, or other irritants

  • Symptoms include blanchable, pruritic, raised, red, or skin-colored papules, wheels or plaques on the skin's surface; usually, disappear within 24 hours
  • (+) Darier's sign: localized urticaria appearing where the skin is rubbed (histamine release)
  • Angioedema: painless, deeper form of urticaria affecting the lips, tongue, eyelids hand and genital

DX: extensive lab testing not indicated; skin or IgE testing limited to the specific history of provoking allergen

TX: Hives usually go away without treatment, but antihistamine medications are often helpful in improving symptoms

  • Second generation antihistamine blockers (H1) are first-line treatment (Allegra, Claritin, Clarinex, Zyrtec)
  • First-generation antihistamine for sleep disturbances: hydroxyzine/diphenhydramine
  • H2 antihistamines as adjuvants: cimetidine, ranitidine
  • Steroids for exacerbations, avoid chronic use

If anaphylaxis give epinephrine: 0.3–0.5 mg; use 1:1,000 dilution for IM route and 1:10,000 for IV route

  • Peds: epinephrine 0.01 mg/kg SC/IV


Itching Presentation:

An uncomfortable, irritating sensation that creates an urge to scratch that can involve any part of the body.

Common causes of this symptom:

  • Itching can have causes that aren't due to underlying disease. Examples include hair regrowth, sunburns, insect bites, dry skin, or healing wounds
  • Itching can result from
    • Skin disorders (most common cause)
    • Disorders of other organs (systemic disorders)
    • Drugs and chemicals

Skin disorders

  • Dry skin ( xeroderma and ichthyosis)
  • Atopic dermatitis (eczema)
  • Contact dermatitis
  • Hives
  • Insect bites scabies

Systemic disorders

  • Allergic reaction ( food, drugs, bites, or stings)
  • Disorders of the liver, such as jaundice
  • Chronic kidney disease
  • psychogenic itching


  • Skincare measures ( moisturizing the skin, and humidifying the air)
  • Itching can usually be relieved by topical creams and steroids or systemic treatments such as Benadryl, steroids, Pepcid, etc.


  • Itching usually results from dry skin, a skin disorder, or an allergic reaction
  • Other causes may be a drug or a systemic disorder
Viral exanthems Erythema infectiosum (fifth disease): Parvovirus B19"slapped cheek" rash on face - lacy reticular rash on extremities, spares palms and soles; resolves 2-3 weeks; supportive care/anti-inflammatories

Hand-foot-mouth disease: children < 10 years old caused by coxsackievirus type A virus-producing sores in the mouth and a rash on the hands, feet, mouth, and buttocks  (watch video); usually clears 10 days; tx = supportive / anti-inflammatories

Measles (rubeola): The 4 C's - cough, coryza, conjunctivitis and cephalocaudal spread

  • Morbilliform - maculopapular, brick red rash on face beginning at hairline then progressing to palms and soles last - rash lasts 7 days
  • Koplik spots (small red spots in buccal mucosa with the blue-white pale center) precedes the rash by 24-48 hours
  • tx = supportive: anti-inflammatories, isolate 1 week after onset of rash

Rubella: 3-day rash; first appears on face spreads caudally to trunk and extremities and becomes generalized in 24 hours; cephalocaudal spread; teratogenic in 1st trimester (deafness, cataracts, TTP, mental retardation)

Roseola (sixth disease): Herpesvirus 6 or 7, only childhood exanthem that starts on the trunk and spreads to the face

  • High fever 3-5 days then rose pink maculopapular blanchable rash on trunk/back and face
Emergency Medicine Rotation: Urology and Renal (PEARLS) (Prev Lesson)
(Next Lesson) Emergency Medicine Rotation: Endocrinology (PEARLS)
Back to Emergency Medicine Rotation

The Daily PANCE and PANRE

Get 60 days of PANCE and PANRE Multiple Choice Board Review Questions delivered daily to your inbox. It's 100% FREE and 100% Awesome!

You have Successfully Subscribed!