• Atopic Dermatitis
  • Cellulitis
  • Contact Dermatitis
  • Necrotizing Fasciitis
  • Steven-Johnson Syndrome

Atopic Dermatitis

  • Background
    • Atopic dermatitis is a chronic relapsing inflammatory skin disorder with a complex pathogenesis involving genetic susceptibility, immunologic and epidermal barrier dysfunction, and environmental factors. 
  • Signs/Symptoms
    • Itchy/scaly rash, particularly on cheeks/trunk and flexor surfaces. Pruritus is the primary symptom.
  • Diagnosis
  • Treatment
    • Identify and eliminate triggers. Topical steroid (hydrocortisone, triamcinolone, etc.). Emollients (Vaseline, Aquaphor) can be used on top of steroids.

Video Credit: Osmosis

*Deep Dive: Atopic Dermatitis (Merck Manual)

person on top of a hill

Photo by Mayu on


  • Background
    • Cellulitis is an infection of the soft tissue beneath the skin, most commonly caused by bacteria that normally colonize the skin surface (ex. Staph aureus).
  • Signs/Symptoms 
    • Tender, warm, erythematous rash with poorly demarcated borders. May have an associated skin abscess. Patients may also experience fever/chills, malaise, or headache.
  • Diagnosis 
    • Clinical diagnosis; ultrasound may aid in the diagnosis by showing a “cobblestone appearance” and identifying potential abscesses 
  • Treatment
    • Cephalexin or amoxicillin for simple cellulitis. For suspected MRSA, use TMP/SMX, clindamycin, or doxycycline.
Video Credit: Zero To Finals

*Deep Dive: Cellulitis (Core EM)

Contact Dermatitis

  • Background
    • Contact dermatitis is inflammation of the skin caused by direct contact with irritants (irritant contact dermatitis) or allergens (allergic contact dermatitis). 
  • Sign/Symptoms
    • Well-demarcated erythematous rash on site of contact, with possible vesicles or erosions. Rash will typically be pruritic.
  • Diagnosis
    • Clinical diagnosis based on history, exam, and exposure history. Allergists/dermatologists may use patch test to determine precise cause.
  • Treatment
    • Removal of irritant/allergen, topical steroids (hydrocortisone, triamcinolone), and emollients. 
Video Credit: Medicosis

*Deep Dive: Contact Dermatitis (Merck Manual)

Necrotizing Fasciitis

  • Background
    • Necrotizing fasciitis is a severe bacterial infection that can lead to tissue destruction, systemic infection and death. It is sometimes referred to as “flesh eating bacteria”. It is typically caused by a mix of bacteria that release a toxin which destroys surrounding tissue.
  • Signs/Symptoms
    • Pain out of proportion to exam. Erythema, swelling/edema, hemorrhagic bullae, lymphadenopathy
  • Diagnosis
    • Ultrasound may show thickened fascia planes. CT is the study of choice, however, surgical exploration is the only definitive method of diagnosing necrotizing fasciitis.
  • Treatment
    • Treat initially with broad-spectrum antibiotic coverage (Piperacillin-Tazobactam + Clindamycin + Vancomycin). Surgical debridement required for definitive treatment.
Video Credit: EM in 5

*Deep Dive: Necrotizing Fasciitis-Pearls & Pitfalls (emDOCs)

Steven Johnson Syndrome

  • Background
    • Steven-Johnson Syndrome (SJS) is a severe skin and mucous membrane reaction that causes necrosis and sloughing of the epidermis (top layer of skin). The most common cause is medications, but can also occur due to infection and in many cases the cause is not known. When skin sloughing involves greater than 30% of the body surface, the term toxic epidermal necrolysis (TEN) is used.
  • Signs/Symptoms
    • Vesicles and bullae involving < 10% of the body on at least 2 mucosal sites. Patients often experience a prodrome (fever, URI symptoms, headache, and malaise)
  • Diagnosis
    • Clinical diagnosis
  • Treatment
    • Removal of cause (usually medications), fluid resuscitation, referral to burn center
Video Credit: Medcrine

*Deep Dive: SJS and TEN (Merck Manual)

Brandon Simpson, PA-S2
Latest posts by Brandon Simpson, PA-S2 (see all)