History

As previously mentioned, local trauma and/or pressure (often in association with lack of sensation because of neuropathy), in addition to microvascular disease, may lead to a diabetic foot infection. However, patients may not necessarily have a history of trauma or have suffered a previous infection.

Cellulitis

Cellulitis may involve tender, erythematous, nonraised skin lesions on the lower extremity that may or may not be accompanied by lymphangitis. Lymphangitis suggests a group A streptococcal etiology. If bullae are present, S aureus is the most likely pathogen, but group A streptococci occasionally cause bullous lesions. No ulcer or wound exudate is present in patients with cellulitis.

Deep-skin and soft-tissue infections

Patients with deep-skin and soft-tissue infections may be acutely ill, with painful induration of the soft tissues in the extremity. These infections are particularly common in the thigh area, but they may be seen anywhere on the leg or foot. Wound discharge is usually not present.

In mixed infections that may involve anaerobes, crepitation may be noted over the afflicted area. Extreme pain and tenderness indicate the possibility of a compartment syndrome. Similarly, extreme pain may be an indication of infection with clostridial species (ie, gas gangrene). The tissues are not tense, and bullae may be present. If a discharge is present, it is often foul.

Acute osteomyelitis

Unless peripheral neuropathy is present, the patient has pain at the site of the involved bone. Usually, fever and regional adenopathy are absent.

Chronic osteomyelitis

In chronic osteomyelitis, the patient's temperature is usually less than 102°F. Discharge is commonly foul. No lymphangitis is observed, and pain may or may not be present, depending on the degree of peripheral neuropathy.

The deep, penetrating ulcers and deep sinus tracts (which are diagnostic of chronic osteomyelitis) are usually located between the toes or on the plantar surface of the foot. In patients with diabetes, chronic osteomyelitis usually does not occur on the medial malleoli, shins, or heels. (See the image below.)

Chronic diabetic ulceration with underlying osteomyelitis. Plain film radiograph exhibiting cortical disruption at the medial aspect of the first MTP joint.

Differential Diagnoses

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Malabu UH, Al-Rubeaan KA, Al-Derewish M. Diabetic foot osteomyelitis: usefulness of erythrocyte sedimentation rate in its diagnosis. West Afr J Med. 2007 Apr-Jun. 26(2):113-6. [QxMD MEDLINE Link].
Lipsky BA, Armstrong DG, Citron DM, Tice AD, Morgenstern DE, Abramson MA. Ertapenem versus piperacillin/tazobactam for diabetic foot infections (SIDESTEP): prospective, randomised, controlled, double-blinded, multicentre trial. Lancet. 2005 Nov 12. 366(9498):1695-703. [QxMD MEDLINE Link].
Lipsky BA, Giordano P, Choudhri S, Song J. Treating diabetic foot infections with sequential intravenous to oral moxifloxacin compared with piperacillin-tazobactam/amoxicillin-clavulanate. J Antimicrob Chemother. 2007 Aug. 60(2):370-6. [QxMD MEDLINE Link]. [Full Text].
Lipsky BA, Stoutenburgh U. Daptomycin for treating infected diabetic foot ulcers: evidence from a randomized, controlled trial comparing daptomycin with vancomycin or semi-synthetic penicillins for complicated skin and skin-structure infections. J Antimicrob Chemother. 2005 Feb. 55(2):240-5. [QxMD MEDLINE Link]. [Full Text].
Stein GE, Schooley S, Peloquin CA, Missavage A, Havlichek DH. Linezolid tissue penetration and serum activity against strains of methicillin-resistant Staphylococcus aureus with reduced vancomycin susceptibility in diabetic patients with foot infections. J Antimicrob Chemother. 2007 Oct. 60(4):819-23. [QxMD MEDLINE Link]. [Full Text].
Wang S, Cunha BA, Hamid NS, Amato BM, Feuerman M, Malone B. Metronidazole single versus multiple daily dosing in serious intraabdominal/pelvic and diabetic foot infections. J Chemother. 2007 Aug. 19(4):410-6. [QxMD MEDLINE Link].
Rasigade JP, Dunyach-Remy C, Sapin A, et al. A Prophage in Diabetic Foot Ulcer-Colonizing Staphylococcus aureus Impairs Invasiveness by Limiting Intracellular Growth. J Infect Dis. 2016 Nov 15. 214 (10):1605-8. [QxMD MEDLINE Link].
Lynar SA, Robinson CH, Boutlis CS, Commons RJ. Risk factors for mortality in patients with diabetic foot infections: a prospective cohort study. Intern Med J. 2018 Dec 4. [QxMD MEDLINE Link].
Morbach S, Furchert H, Gröblinghoff U, Hoffmeier H, Kersten K, Klauke GT, et al. Long-Term Prognosis of Diabetic Foot Patients and Their Limbs: Amputation and death over the course of a decade. Diabetes Care. 2012 Jul 18. [QxMD MEDLINE Link].
Chammas NK, Hill RL, Edmonds ME. Increased Mortality in Diabetic Foot Ulcer Patients: The Significance of Ulcer Type. J Diabetes Res. 2016. 2016:2879809. [QxMD MEDLINE Link]. [Full Text].
Chen SY, Giurini JM, Karchmer AW. Invasive Systemic Infection After Hospital Treatment for Diabetic Foot Ulcer: Risk of Occurrence and Effect on Survival. Clin Infect Dis. 2017 Feb 1. 64 (3):326-334. [QxMD MEDLINE Link].
Nelson A, Wright-Hughes A, Backhouse MR, et al. CODIFI (Concordance in Diabetic Foot Ulcer Infection): a cross-sectional study of wound swab versus tissue sampling in infected diabetic foot ulcers in England. BMJ Open. 2018 Jan 31. 8 (1):e019437. [QxMD MEDLINE Link]. [Full Text].
[Guideline] Lipsky BA, Senneville E, Abbas ZG, et al. IWGDF guideline on the diagnosis and treatment of foot infection in persons with diabetes. International Working Group on the Diabetic Foot. Available at https://iwgdfguidelines.org/wp-content/uploads/2019/05/05-IWGDF-infection-guideline-2019.pdf. 2019; Accessed: January 16, 2020.
[Guideline] Hingorani A, LaMuraglia GM, Henke P, Meissner MH, Loretz L, Zinszer KM, et al. The management of diabetic foot: A clinical practice guideline by the Society for Vascular Surgery in collaboration with the American Podiatric Medical Association and the Society for Vascular Medicine. J Vasc Surg. 2016 Feb. 63 (2 Suppl):3S-21S. [QxMD MEDLINE Link].
Matos M, Mendes R, Silva AB, Sousa N. Physical activity and exercise on diabetic foot related outcomes: a systematic review. Diabetes Res Clin Pract. 2018 Feb 22. [QxMD MEDLINE Link].
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[Guideline] Tucker ME. New guidelines stress need for diabetic foot ulcer offloading. Medscape Medical News. 2014 Dec 26. [Full Text].
Snyder RJ, Frykberg RG, Rogers LC, Applewhite AJ, Bell D, Bohn G. The management of diabetic foot ulcers through optimal off-loading: building consensus guidelines and practical recommendations to improve outcomes. J Am Podiatr Med Assoc. 2014 Nov. 104(6):555-67. [QxMD MEDLINE Link].
Rogers LC, Frykberg RG, Armstrong DG, et al. The Charcot foot in diabetes. Diabetes Care. 2011 Sep. 34(9):2123-9. [QxMD MEDLINE Link].
Lipsky BA, Berendt AR, Cornia PB, et al. 2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections. Clin Infect Dis. 2012 Jun. 54(12):e132-73. [QxMD MEDLINE Link].
Tucker M. Short-Course Antibiotics Good in Diabetic Foot Osteomyelitis. Medscape Medical News. 2014 Nov 26. [Full Text].
Tone A, Nguyen S, Devemy F, Topolinski H, Valette M, Cazaubiel M, et al. Six- Versus Twelve-Week Antibiotic Therapy for Nonsurgically Treated Diabetic Foot Osteomyelitis: A Multicenter Open-Label Controlled Randomized Study. Diabetes Care. 2014 Nov 20. [QxMD MEDLINE Link].
[Guideline] Allahabadi S, Haroun KB, Musher DM, Lipsky BA, Barshes NR. Consensus on surgical aspects of managing osteomyelitis in the diabetic foot. Diabet Foot Ankle. 2016. 7:30079. [QxMD MEDLINE Link]. [Full Text].
US Food and Drug Administration. FDA Drug Safety Communication: Serious CNS reactions possible when linezolid (Zyvox®) is given to patients taking certain psychiatric medications. Available at http://www.fda.gov/Drugs/DrugSafety/ucm265305.htm. Accessed: July 27, 2011.
Lázaro-Martínez J, Aragón-Sánchez J, García-Morales E. Antibiotics versus conservative surgery for treating diabetic foot osteomyelitis. A randomized comparative trial. Diabetes Care. 2013 Oct 15. [QxMD MEDLINE Link].
Nainggolan L. Antibiotics First Choice for Diabetic Foot Osteomyelitis. Medscape Medical News. 2013 Oct 24. [Full Text].

Media Gallery

Chronic diabetic ulceration with underlying osteomyelitis. Plain film radiograph exhibiting cortical disruption at the medial aspect of the first MTP joint.

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Author

Michael Stuart Bronze, MD David Ross Boyd Professor and Chairman, Department of Medicine, Stewart G Wolf Endowed Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center; Master of the American College of Physicians; Fellow, Infectious Diseases Society of America; Fellow of the Royal College of Physicians, London

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Medical Association, Association of Professors of Medicine, Infectious Diseases Society of America, Oklahoma State Medical Association, Southern Society for Clinical Investigation

Disclosure: Nothing to disclose.

Coauthor(s)

Burke A Cunha, MD Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital

Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Richard B Brown, MD, FACP Chief, Division of Infectious Diseases, Baystate Medical Center; Professor, Department of Internal Medicine, Tufts University School of Medicine

Richard B Brown, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Chest Physicians, American College of Physicians, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, Massachusetts Medical Society

Disclosure: Nothing to disclose.

Chief Editor

Romesh Khardori, MD, PhD, FACP (Retired) Professor, Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Eastern Virginia Medical School

Romesh Khardori, MD, PhD, FACP is a member of the following medical societies: American Association of Clinical Endocrinologists, American College of Physicians, American Diabetes Association, Endocrine Society

Disclosure: Nothing to disclose.

Additional Contributors

Charles S Levy, MD Associate Professor, Department of Medicine, Section of Infectious Disease, George Washington University School of Medicine

Charles S Levy, MD is a member of the following medical societies: American College of Physicians, Infectious Diseases Society of America, Medical Society of the District of Columbia

Disclosure: Nothing to disclose.