The Red Leg

1. The Red Leg Medical Student Core Curriculum in Dermatology Last updated June 16, 2011

2. Module Instructions • The following module contains a number of blue, underlined terms which are hyperlinked to the dermatology glossary, an illustrated guide to clinical dermatology and dermatopathology. • We encourage the learner to read all the hyperlinked information.

3. Goals and Objectives • The purpose of this module is to help medical students develop a clinical approach to the evaluation and initial management of patients presenting with an erythematous leg. • By completing this module, the learner will be able to: • Recognize common and life-threatening causes of an erythematous leg • List the various risk factors for the conditions presented in this module • Describe the initial treatment plans for each condition presented in this module • Determine when to refer patients presenting with a red leg to a dermatologist or other specialty

4. Case One Mr. Roy Clarke

5. Case One: History • HPI: Mr. Clarke is a 55-year-old man who presents with 5 days of worsening right lower extremity pain and a red rash. He reports recent fevers and chills since he returned from a camping trip last week. • PMH: arthritis • Medications: occasional NSAIDs, multivitamin • Allergies: no known drug allergies • Family history: father with history of melanoma • Social history: lives in the city with his wife, two grown children • Health-related behaviors: no alcohol, tobacco or drug use • ROS: able to bear weight, no itching

6. Case One: Exam Vital signs: T 100.4, HR 90, BP 120/70, RR 14, O2 sat 97% on RA Skin: erythematous plaque with ill-defined borders over the right medial malleolus. Lesion is tender to palpation. With lymphatic streaking (not shown). Tender, slightly enlarged right inguinal lymph nodes (not shown) Laboratory data: Wbc 12,000 (75% neutrophils, 10% bands), Hct 44, Plts 335

7. Case One, Question 1 • What is the most likely diagnosis? • Bacterial folliculitis • Cellulitis • Necrotizing fasciitis • Stasis dermatitis • Tinea corporis

8. Case One, Question 1 Answer: b • What is the most likely diagnosis? • Bacterial folliculitis(Would expect pustules and papules centered on hair follicles. Without systemic signs of infection.) • Cellulitis • Necrotizing fasciitis (Would expect rapidly expanding rash, usually appears as a dusky, edematous, red plaque. In this setting, it is always appropriate to ask the question, “Could this be necrotizing fasciitis?”) • Stasis dermatitis(Although found in similar location, stasis dermatitis often presents with pruritus and scale, which may erode or crust. Without fever or elevated wbc.) • Tinea corporis(Would expect annular plaque with elevated border and central clearing. Painless, without fever or elevated wbc.)

9. Diagnosis: Cellulitis • Cellulitis is a very common infection occurring in up to 3% of people per year • Results from an infection of the dermis that often begins with a portal of entry such as a wound or fungal infection (e.g., tinea pedis) • Group A beta-hemolytic streptococci and Staphyloccocus aureus are the most common causal pathogens • Presents as a spreading erythematous, non-fluctuant tender plaque • More commonly found on the lower leg • Streaks of lymphangitis may spread from the area to the neighboring lymph glands

10. Erysipelas • Erysipelas is a superficial cellulitis with marked dermal lymphatic involvement (causing the skin to be edematous or raised) • Main pathogen is group A streptococcus • Usually affects the lower extremities and the face • Presents with pain, superficial erythema, and plaque-like edema with a sharply defined margin to normal tissue • Plaques may develop overlying blisters (bullae) • May be associated with a high white count (>20,000/mcL) • May be preceded by chills, fever, headache, vomiting, and joint pain

11. Example of Erysipelas Large, shiny erythematous plaque with sharply demarcated borders located on the posterior leg

12. Back to Case One Mr. Clarke was diagnosed with cellulitis.

13. Case One, Question 2 • What is the next best step in management? • Apply topical antibiotics • Apply topical steroids, compression wraps, and encourage leg elevation • Begin antibiotics immediately with coverage for gram positive bacteria • Order an imaging study

14. Case One, Question 2 Answer: c • What is the next best step in management? • Apply topical antibiotics (not effective) • Apply topical steroids, compression wraps, and encourage leg elevation (this is the treatment for stasis dermatitis, not cellulitis) • Begin antibiotics immediately with coverage for gram positive bacteria • Order an imaging study (radiographic examination is not necessary for routine evaluation of patients with cellulitis)

15. Cellulitis: Treatment • It is important to recognize and treat cellulitis early as untreated cellulitis may lead to sepsis and death • May use the following guidelines for empiric antibiotic therapy: • For outpatients with nonpurulent cellulitis: empirically treat for β-hemolytic streptococci (group A streptococcus) • Some clinicians choose an agent that is also effective against S. aureus • For outpatients with purulent cellulitis (purulent drainage or exudate in the absence of a drainable abscess): empirically treat for community-associated MRSA • For unusual exposures: cover for additional bacterial species likely to be involved

16. Cellulitis: Treatment (cont.) • Monitor patients closely and revise therapy if there is a poor response to initial treatment • Elevation of the involved area • Treat tinea pedis if present • For hospitalized patients: empiric therapy for MRSA should be considered • Cultures from abscesses and other purulent skin and soft tissue infections (SSTIs) are recommended in patients treated with antibiotic therapy

17. Case Two Mr. Anthony Bice

18. Case Two: History • HPI: Mr. Bice is a 66-year-old man who was admitted for an inguinal hernia repair. His surgery went well and he was recovering without complication until he was found to have an expanding red rash on his left thigh. The dermatology service was consulted for evaluation of the rash. • PMH: hypertension, diabetes mellitus type 2 • Medications: lisinopril, insulin, oxycodone • Allergies: none • Family history: noncontributory • Social history: retired, lives with his wife • Health-related behaviors: reports no alcohol, tobacco, or drug use • ROS: febrile, fatigue, rash is painful

19. Case Two: Exam • Vital signs: T 101.1, HR 110, BP 90/50, RR 18, O2 sat 98% • General: ill-appearing gentleman lying in bed • Skin: ill-defined, anesthetic, large erythematous plaque with central patches of dusky blue discoloration; upon re-examination 60 minutes later, the redness had spread

20. Case Two, Question 1 • Which of the following do you recommend for initial management? • Call an urgent surgery consult • Give IV fluids and antibiotics • Image with stat MRI • Obtain a deep skin biopsy • All of the above

21. Case Two, Question 1 Answer: e • Which of the following do you recommend for initial management? • Call an urgent surgery consult (The suspected diagnosis is a surgical emergency.) • Give IV fluids and antibiotics (Patients quickly become hemodynamically unstable.) • Image with stat MRI (To assess degree of soft tissue involvement. Appropriate, but do not delay surgical intervention.) • Obtain a deep skin biopsy (Helps confirm diagnosis.) • All of the above

22. Diagnosis: Necrotizing Fasciitis • Necrotizing fasciitis is a life-threatening infection of the fascia just above the muscle • Progresses rapidly over the course of hours and may follow surgery or trauma, or have no preceding visible lesion • Expanding dusky, edematous, red plaque with blue discoloration • May turn purple and blister • Anesthesia of the skin of the affected area is a characteristic finding • Caused by group A streptococcus, Staphylococcus aureus, or a variety of other organisms

23. Necrotizing Fasciitis: Treatment • Considered a medical/surgical emergency with up to a 20% fatality rate • If suspect necrotizing fasciitis, consult surgery immediately • Treatment includes widespread debridement and broad-spectrum systemic antibiotics • Poor prognostic factors include: delay in diagnosis, age > 50, diabetes, atherosclerosis, infection involving the trunk

24. Case Three Ms. Janet Frasier

25. Case Three: History • HPI: Ms. Frasier is a 43-year-old woman with a recent diagnosis of gout who presents to her primary care provider with a diffuse rash on her lower extremities. The rash began 4 days after starting indomethacin for an acute gout attack. • PMH: gout, no hospitalizations or surgeries • Medications: indomethacin, zolpidem • Allergies: none • Social history: lives by herself in an apartment • Health-related behaviors: history of significant alcohol use, last drink 3 years ago. No tobacco or drug use. • ROS: no current fevers, sweats or chills

26. Case Three: Skin Exam • Normal vital signs • General: appears well in NAD • Skin exam: palpable hemorrhagic papules coalescing into plaques, bilateral and symmetric on lower extremities

27. Case Three, Question 1 • Which of the following is the most likely cause of Ms. Frasier’s skin findings? • DIC secondary to sepsis • Leukocytoclastic vasculitis secondary to NSAID • Septic emboli with hemorrhage from undiagnosed bacterial endocarditis • Urticarial vasculitis

28. Case Three, Question 1 Answer: b • Which of the following is the most likely cause of Ms. Frasier’s skin findings? • DIC secondary to sepsis (Ms. Frasier’s history and exam are less concerning for sepsis. Skin lesions of DIC tend to occur on acral and distal sites, with a retiform (netlike) purpura.) • Leukocytoclastic vasculitis secondary to NSAID • Septic emboli with hemorrhage from undiagnosed bacterial endocarditis (Ms. Frasier has no known risk factors for endocarditis and lesions tend to occur on the distal extremities.) • Urticarial vasculitis (Presents with a different morphology, which is urticarial.)

29. Palpable Purpura • Palpable purpura results from inflammation of small cutaneous vessels, i.e. vasculitis • Vessel inflammation results in vessel wall damage and in extravasation of erythrocytes seen as purpura on the skin • Vasculitis may occur as a primary process or may be secondary to another underlying disease • Palpable purpura is the hallmark lesion of leukocytoclastic vasculitis (small vessel vasculitis)

30. Vasculitides According to Size of the Blood Vessels • Small vessel vasculitis (leukocytoclastic vasculitis) • Henoch-Schönlein purpura • Other: • Idiopathic • Malignancy-related • Rheumatologic • Infection • Medication • Urticarial vasculitis

31. Vasculitides According to Size of the Blood Vessels • Predominantly Mixed (Small + Medium) • ANCA associated vasculitides • Churg-Strauss syndrome • Microscopic polyangiitis • Wegener granulomatosis • Essential cryoglobulinemic vasculitis • Predominantly medium sized vessels • Polyarteritis nodosa • Predominantly large vessels • Giant cell arteritis • Takayasu arteritis

32. Clinical Evaluation of Vasculitis • The following laboratory tests may be used to evaluate patient with suspected vasculitis: • CBC with platelets • ESR (systemic vasculitides tend to have sedimentation rates > 50) • ANA (a positive antinuclear antibody test suggests the presence of an underlying connective tissue disorder) • ANCA (helps diagnose Wegener granulomatosis, microscopic polyarteritis, drug-induced vasculitis, and Churg-Strauss) • Complement (low serum complement levels may be present in mixed cryoglobulinemia, urticarial vasculitis and lupus) • Urinalysis (helps detect renal involvement) • Also consider ordering cryoglobulins, an HIV test, HBV and HCV serology, occult stool samples, an ASO titer and streptococcal throat culture

33. Diagnosis: Leukocytoclastic Vasculitis (LCV) • The primary care provider also suspects LCV secondary to medication hypersensitivity, but to make sure she has not missed any other causes of vasculitis she orders laboratory tests and refers the patient to a dermatologist • Ms. Frasier was recommended to stop the indomethacin

34. Case Four Mrs. Belinda Strong

35. Case Four: History • HPI: Mrs. Strong is a 60-year-old woman who presents with a “rash” on her leg that has been present for 2 months. She reports no pain, but does experience mild pruritus. • PMH: diabetes (last hemoglobin A1c was 6.7), hypertension, obesity. No history of atopic dermatitis. • Medications: lisinopril, metoprolol, glyburide • Allergies: none • Family history: mother with diabetes and hypertension • Social history: lives with her husband in the city, four grown children, two grandchildren • Health-related behaviors: no tobacco, alcohol or drug use • ROS: no leg pain when walking or at rest

36. Case Four, Question 1 How would you describe these skin findings?

37. Case Four, Question 1 Large erythematous plaques with fine fissuring and scale as well as interspersed brown macular hyperpigmentation

38. Case Four, Question 2 • What is the most likely diagnosis? • Atopic dermatitis • Bilateral cellulitis • Stasis dermatitis • Tinea corporis

39. Case Four, Question 2 Answer: c • What is the most likely diagnosis? • Atopic dermatitis(adults with AD have a history of childhood AD and a different distribution of skin involvement) • Bilateral cellulitis(cellulitis occurs more acutely, presents with fever and pain, more erythema, well-demarcated and without pruritus or scale) • Stasis dermatitis • Tinea corporis(would expect sharply marginated, erythematous annular patches with central clearing)

40. Diagnosis: Stasis Dermatitis • Stasis dermatitis typically presents with erythema, scale, pruritus, erosions, exudate, and crust • Usually located in the lower third of the legs, superior to the medial malleolus • Can occur bilaterally or unilaterally • Lichenification may develop • Edema is often present, as well as varicose veins and hemosiderin deposits (pinpoint yellow-brown macules and papules)

41. More Examples of Stasis Dermatitis

42. More Examples of Stasis Dermatitis

43. Case Four, Question 3 • Which of the following treatments do you recommend for Mrs. Strong ? • Leg elevation, compression therapy • Leg elevation, topical antibiotics • Leg elevation, topical corticosteroids, compression therapy • Topical corticosteroids

44. Case Four, Question 3 Answer: c • Which of the following treatments do you recommend for Mrs. Strong? • Leg elevation, compression therapy • Leg elevation, topical antibiotics • Leg elevation, topical corticosteroids, compression therapy • Topical corticosteroids

45. Stasis Dermatitis: Treatment • Important to treat both the dermatitis and the underlying venous insufficiency • Application of super-high and high potency steroids to area of dermatitis under a wrap • Elevation (to reduce edema) • Compression therapy with leg wraps* • Change wraps weekly, or more often if the lesion is very weepy * Establish pedal pulses prior to using compression wraps. See the Stasis Dermatitis and Leg Ulcers module for more information.

46. Case Four (cont.) • Mrs. Strong returns for a follow-up visit 6 months later. She was able to adhere to the regimen of topical corticosteroids, leg elevation and compression therapy for the first few weeks, but then became preoccupied with a new grandbaby and stopped the treatment altogether. • A few months later she noticed a weeping wound on the same leg. She has been applying an over-the-counter topical ointment. • She now reports mild pain and worsening pruritus.

47. Case Four: Exam Vital signs: normal Skin: erythematous plaque located on the medial left leg with a shallow ulcer with a fibrinous base and some serous exudate

48. Case Four, Question 4 • What is the most likely diagnosis? • Cellulitis • Contact dermatitis • Necrotizing fasciitis • Vasculitis

49. Case Four, Question 4 Answer: b • What is the most likely diagnosis? • Cellulitis (history of topical ointment and pruritus are more consistent with contact dermatitis, also patient is afebrile) • Contact dermatitis • Necrotizing fasciitis (would expect fever and other systemic signs and symptoms) • Vasculitis (would expect palpable purpura)

50. Contact Dermatitis • Mrs. Strong has a contact dermatitis secondary to an over-the-counter antibiotic ointment. • Patients with leg ulcers have a high incidence of allergic contact dermatitis due to frequent and prolonged use of topical products as well as a disrupted skin barrier in the areas of use. • Leg ulcers may become persistent or recurrent due to ongoing dermatitis and exposure to contact allergens.