• Clinical science

Skin and soft tissue infections

Abstract

Skin and soft tissue infections comprise a group of heterogeneous conditions that primarily develop as a result of pathogens infiltrating the skin via minor injuries. Most skin infections are caused by Staphylococcus, but they may also be caused by Streptococcus or mixed infections in select cases. Risk factors include diabetes mellitus, immunodeficiency, and chronic edema. Skin and soft tissue infections primarily present as painful, warm, erythematous skin lesions. Systemic symptoms, such as fever and malaise, may also occur. Elevated inflammatory markers in the blood support the clinical diagnosis. Imaging may be considered to establish the extent and localization of infection. Treatment includes antibiotic therapy and immobilization of the affected area while severe cases and abscesses require surgery (debridement or incision and drainage). With the exception of necrotizing fasciitis, the majority of cases respond well to treatment and have a favorable prognosis. In the event of generalization, sepsis and spread of infection to local and distant sites may result.

Overview

General

Treatment of skin and soft tissue infections

Mild infection Moderate infection Severe infection
Nonpurulent infections (erysipelas, cellulitis, necrotizing fasciitis)
  1. Surgical debridement (with culture and sensitivity testing)
  2. Empiric antibiotic treatment: vancomycin PLUS piperacillin/tazobactam[1]
Purulent infections (furuncle, carbuncle, abscess)
  • Incision and drainage
  1. Incision and drainage
  2. Empiric antibiotic treatment: TMP/SMX or doxyclycine
  1. Incision and drainage
  2. Empiric antibiotic treatment covering MRSA: vancomycin or daptomycin or linezolid or televancin or ceftaroline

Adapt antibiotic treatment according to the results of the culture and sensitivity testing.

References:[2][3][4][5][6][7]

Differential diagnoses

Pathogen Tissue involvement Clinical features
Erysipelas
  • Superficial dermis and lymphatic vessels
Cellulitis
  • Rapidly spreading infection; erythematous skin lesion with indistinct margins
  • May present with or without purulent exudate
Necrotizing fasciitis
  • Deeper tissue, fascia, muscles
  • Severe, rapidly progressive infection with necrosis; crepitus, bullae, and purple skin discoloration
  • High risk of systemic complications; high mortality
Folliculitis
Skin abscess
  • Deeper layers of the skin
  • Walled-off infection with a collection of pus
Impetigo
Staphylococcal scalded skin syndrome

The differential diagnoses listed here are not exhaustive.

Folliculitis

References:[8][9][10][11][12][13]

Skin abscess

In both scrotal abscess and epididymitis, the classic signs of inflammation are prominent and of considerable diagnostic value!

References:[12][14][15]

Erysipelas

The most common portal of entry for the pathogen is through a small skin lesion (e.g., interdigital tinea pedis)!

  • Clinical features
    • Location: lower limbs (80% of cases), face
    • Sudden onset; tender, sharply demarcated skin lesion, with erythema, edema, and warmth
    • The erythematous lesion may form bullae. These bullae may occasionally become hemorrhagic.
    • Lymphangitis; : Red streaks radiating from the skin lesion, extending along the course of the lymphatic vessels, and lymphadenitis (swollen, tender regional lymph nodes) may be present.
    • Systemic symptoms: fever, chills, nausea, headaches, muscle and joint pain
  • Milian's ear sign: involvement of the ear lobe in facial erysipelas; this sign allows facial erysipelas to be differentiated from facial cellulitis

References:[2][4][7][16][17]

Cellulitis

References:[18][4][14][19][20][21][22]

Necrotizing fasciitis

Necrotizing fasciitis is a life-threatening condition!

References:[23][14][24][23][1][25]

Empyema

Ecthyma gangrenosum

  • Definition: an ulcerative lesion extending into the dermis that develops in the setting of bacteremia
  • Pathogen: Pseudomonas aeruginosa (not pathognomonic but is the most common causative organism)
  • Pathophysiology:
  • Clinical features
    • Rapid progression (within 12–18 hours) of painless red macules → induration, development of pustules, vesicles, and/or bullae → crusted ulcers
    • Can involve skin; or mucous membranes; anogenital and axillary areas most commonly involved
    • Can be solitary or multiple
    • Patients typically also systemically ill (e.g., septic shock)
  • Diagnosis: primarily a clinical diagnosis
  • Treatment: see Treatment of skin and soft tissue infection

  • 1. Anaya DA, Dellinger EP. Necrotizing soft-tissue infection: diagnosis and management. Clin Infect Dis. 2007; 44(5): pp. 705–710. doi: 10.1086/511638.
  • 2. Davis L. Erysipelas. In: James WD. Erysipelas. New York, NY: WebMD. http://emedicine.medscape.com/article/1052445. Updated June 29, 2016. Accessed January 27, 2017.
  • 3. Jorup-rönström C. Epidemiological, bacteriological and complicating features of erysipelas. Scand J Infect Dis. 1986; 18(6): pp. 519–524. pmid: 3810046.
  • 4. Baddour LM. Cellulitis and erysipelas. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/cellulitis-and-erysipelas. Last updated January 12, 2017. Accessed January 27, 2017.
  • 5. Shipman AR, Millington GW. Obesity and the skin. Br J Dermatol. Br J Dermatol. 2011; 165(4): pp. 743–750. doi: 10.1111/j.1365-2133.2011.10393.x.
  • 6. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014; 59(2): pp. e10–52. doi: 10.1093/cid/ciu444.
  • 7. Bonnetblanc JM, Bédane C. Erysipelas: recognition and management. Am J Clin Dermatol. 2003; 4(3): pp. 157–163. pmid: 12627991.
  • 8. Satter EK. Folliculitis. In: Elston DM. Folliculitis. New York, NY: WebMD. http://emedicine.medscape.com/article/1070456. Updated February 9, 2016. Accessed January 27, 2017.
  • 9. Yu Y, Cheng AS, Wang L, Dunne WM, Bayliss SJ. Hot tub folliculitis or hot hand-foot syndrome caused by Pseudomonas aeruginosa. J Am Acad Dermatol. 2007; 57(4): pp. 596–600. doi: 10.1016/j.jaad.2007.04.004.
  • 10. Jackson JD. Infectious folliculitis. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/infectious-folliculitis. Last updated October 1, 2015. Accessed January 29, 2017.
  • 11. Pinney SS. Malassezia (Pityrosporum) Folliculitis. In: James WD. Malassezia (Pityrosporum) Folliculitis. New York, NY: WebMD. http://emedicine.medscape.com/article/1091037-overview#showall. Updated April 12, 2016. Accessed January 29, 2017.
  • 12. Baddour LM. Skin abscesses, furuncles, and carbuncles. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/skin-abscesses-furuncles-and-carbuncles. Last updated June 30, 2016. Accessed January 27, 2017.
  • 13. Lopez FA, Lartchenko S. Skin and soft tissue infections. Infect Dis Clin North Am. 2006; 20(4): pp. 759–772, v–vi. doi: 10.1016/j.idc.2006.09.006.
  • 14. Jenkins B, McInnis M, Lewis C. Step-Up to USMLE Step 2 CK. Lippincott Williams & Wilkins; 2015.
  • 15. Squire BT, Fox JC, Anderson C. ABSCESS: applied bedside sonography for convenient evaluation of superficial soft tissue infections. Acad Emerg Med. 2005; 12(7): pp. 601–606. doi: 10.1197/j.aem.2005.01.016.
  • 16. Chartier C, Grosshans E. Erysipelas: an Update. Int. J. Dermatol. 1996; 35(11): pp. 779–781. doi: 10.1111/j.1365-4362.1996.tb02971.x.
  • 17. Gunderson CG, Chang JJ. Risk of deep vein thrombosis in patients with cellulitis and erysipelas: a systematic review and meta-analysis. Thromb Res. 2013; 132(3): pp. 336–340. doi: 10.1016/j.thromres.2013.07.021.
  • 18. Le T, Bhushan V, Chen V, King M. First Aid for the USMLE Step 2 CK. McGraw-Hill Education; 2015.
  • 19. Ellis simonsen SM, Van orman ER, Hatch BE, et al. Cellulitis incidence in a defined population. Epidemiol Infect. 2006; 134(2): pp. 293–299. doi: 10.1017/S095026880500484X.
  • 20. Le T, Bhushan V. First Aid for the USMLE Step 1 2015. McGraw-Hill Education; 2014.
  • 21. Harrington JN. Orbital Cellulitis. In: Ing E. Orbital Cellulitis. New York, NY: WebMD. http://emedicine.medscape.com/article/1217858-overview#a7. Updated March 11, 2016. Accessed January 27, 2017.
  • 22. Spelman D,Baddour LM, Sexton DJ, Kaplan SL, Baron EL. Cellulitis and Skin Abscess: Clinical Manifestations and Diagnosis. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/cellulitis-and-skin-abscess-clinical-manifestations-and-diagnosis. Last updated March 8, 2018. Accessed April 3, 2018.
  • 23. Edlich RF. Necrotizing Fasciitis. In: Bronze MS. Necrotizing Fasciitis. New York, NY: WebMD. http://emedicine.medscape.com/article/2051157. Updated August 9, 2016. Accessed January 27, 2017.
  • 24. Laucks SS. Fournier's gangrene. Surg Clin North Am. 1994; 74(6): pp. 1339–1352. pmid: 7985069.
  • 25. Pais VM Jr. Fournier Gangrene. In: Fournier Gangrene. New York, NY: WebMD. http://emedicine.medscape.com/article/2028899. Updated November 12, 2016. Accessed April 4, 2017.
  • Herold G. Internal Medicine. Cologne, Germany: Herold G; 2014.
last updated 12/04/2018
{{uncollapseSections(['jTa_qP', 'lqXvA_', 'yhcdgX0', 'NqX-A_', 'MqXM__', 'xhcETX0', 'mqXV__', 'BhczTX0', '5qXi__', 'hFcc3V0'])}}