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Gram-Negative Toe Web Infection

  • Author: Robert A Schwartz, MD, MPH; Chief Editor: William D James, MD  more...
Updated: Jun 09, 2016


Gram-negative interweb foot impetigo is a relatively common and troubling disorder.[1] The infection is commonly associated with the use of closed-toe or tight-fitting shoes and in individuals in whom strong physical exertion plays an important role in athletic, occupational, or recreational activities.

Gram-negative mixed bacterial infection with organisms, such as Moraxella, Alcaligenes, Acinetobacter, Pseudomonas, Proteus, and Erwinia species, may represent a mild secondary infection of tinea pedis. Over time, in the setting of moisture and maceration, multiple fungal and bacterial organisms may proliferate.[2] The process may progress to advanced stages of gram-negative infection with sepsis. Note the image below.

A 33-year-old man with interweb exudative patches. A 33-year-old man with interweb exudative patches. Courtesy of Rajendra Kapila, MD, Professor of Infectious Diseases, New Jersey Medical School.


Typically, the interweb space is colonized by polymicrobial flora. Initially, a dermatophyte infection at this site may damage the stratum corneum and produce natural substances with antibiotic properties that alter the composition of the resident bacterial flora, encouraging the proliferation of antibiotic-resistant strains.[3]

Gram-negative bacteria may resist the antibacterial agents and many of the commonly used therapeutic agents. In other cases, marked hyperhidrosis with cutaneous maceration, often seen in people who enjoy vigorous athletic endeavors, may predispose individuals to gram-negative bacterial toe web infection. Pseudomonas aeruginosa, often together with other gram-negative bacteria, is the most common etiologic agent.[1]

The toe web space provides a hospitable niche for gram-negative microorganisms; infection can quickly progress from mild overgrowth of resident bacteria to an advanced, severe, gram-negative infection. Lesions that affect the interdigital spaces can occasionally extend to the planta and the backs of the toes. The most frequent complaint of patients is burning and pain, and, in severe infection, problems with walking are noted.

Gram-negative bacteria gain access to the bloodstream from foci of tissue infection or possibly from heavy colonization. Trauma, tinea pedis, or depressed host resistance, as in diabetes mellitus or HIV disease, may also predispose individuals to the infection.

A US military survey for gram-negative bacteria colonization in healthy, asymptomatic military personnel (101 in the United States and 100 in Afghanistan) showed toe web spaces colonized in 35% with non–multidrug-resistant bacteria.[4]




United States

Few data are available on the frequency of gram-negative toe web infections.


A limited number of cases have been reported.


Gram-negative toe web infection can affect any race.


Men appear to be more frequently affected, with a male-to-female ratio of 4:1 reported in one study.[1]


Gram-negative toe web infection affects young and elderly persons. In one series, patients were reported to be aged 1-74 years. The disorder rarely involves infants or children.



In most patients, the prognosis is excellent. With appropriate therapy, complete recovery is usually attained.


Patient Education

Patients should be instructed about proper hygiene, which is a primary preventive measure. For patient education resources, see the Bacterial and Viral Infections Center and Skin, Hair, and Nails Center, as well as Impetigo and Antibiotics.

Contributor Information and Disclosures

Robert A Schwartz, MD, MPH Professor and Head of Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, Rutgers New Jersey Medical School; Visiting Professor, Rutgers University School of Public Affairs and Administration

Robert A Schwartz, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, New York Academy of Medicine, American Academy of Dermatology, American College of Physicians, Sigma Xi

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: American Medical Association, Alpha Omega Alpha, Association of Military Dermatologists, American Academy of Dermatology, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Phi Beta Kappa

Disclosure: Nothing to disclose.

Rosalie Elenitsas, MD Herman Beerman Professor of Dermatology, University of Pennsylvania School of Medicine; Director, Penn Cutaneous Pathology Services, Department of Dermatology, University of Pennsylvania Health System

Rosalie Elenitsas, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, American Society of Dermatopathology, Pennsylvania Academy of Dermatology

Disclosure: Received royalty from Lippincott Williams Wilkins for textbook editor.

Chief Editor

William D James, MD Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

William D James, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Takeji Nishikawa, MD Emeritus Professor, Department of Dermatology, Keio University School of Medicine; Director, Samoncho Dermatology Clinic; Managing Director, The Waksman Foundation of Japan Inc

Disclosure: Nothing to disclose.


The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous authors, Dr. Frantisek Vosmik, and Jarrett R. Hesselbirg, MD, to the development and writing of this article.

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A 33-year-old man with interweb exudative patches. Courtesy of Rajendra Kapila, MD, Professor of Infectious Diseases, New Jersey Medical School.
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