It is a severe disease with rapid onset. The symptoms usually include red or purple skin in the affected area, severe pain, fever, and vomiting. The most affected areas of the body are the limbs and perineum. The bacteria that cause this infection typically enter the body through a break in the skin, such as a cut or burn. The risk factors may be poor immune function, diabetes, cancer, obesity, intravenous drug use, alcoholism, and peripheral artery disease.
This disease does not spread between people. This disease is usually treated with surgery to remove the infected tissue and intravenous antibiotics such as penicillin G, clindamycin, vancomycin, and gentamycin.
Cellulitis is a bacterial infection of inner layers of skin that specifically affects the dermis and subcutaneous fat, while necrotizing fasciitis is a bacterial infection of inner layers of skin that specifically affects subcutaneous tissue or hypodermis. So, this is the key difference between cellulitis and necrotizing fasciitis. Furthermore, cellulitis has a good prognosis, while necrotizing fasciitis has a poor prognosis. The following infographic lists the differences between cellulitis and necrotizing fasciitis in tabular form for side by side comparison.
Skin and soft tissue infections are due to microbial infections of the skin. Ann Surg. Necrotizing fasciitis in children in eastern Ontario: a case—control study.
Google Scholar. Management of cellulitis in a pediatric emergency department. Pediatr Emerg Care. Necrotizing fasciitis. Pediatric orthopedic surgical emergencies. New York: Springer; Emergency management of pediatric skin and soft tissue infections in the community-associated methicillin-resistant Staphylococcus aureus era.
CrossRef Google Scholar. Progression of NF is marked with the development of tense edema, a grayish-brown discharge, vesicles, bullae, necrosis, and crepitus [ 23 ] Table 5.
Hemorrhagic bullae and crepitus are serious signs, with the likelihood of underlying fascia and muscle being compromised [ 24 ]. Although crepitus and blistering are the most specific signs of necrotizing soft tissue infection, they are not sensitive. Two retrospective case series, by Wang et al. There is usually absence of collection of pus which delays surgical consult or delays intervention by surgeon.
Severe localized pain is another feature of NF. As the disease is a deep-seated infection, the epidermis is minimally involved at initial presentation. The patient might complain of pain out of proportion to the degree of dermal involvement or pain that extends past the apparent margin of infection. Patients with diabetic neuropathy may have minimal pain resulting in a missed diagnosis. This is especially likely in concealed sites of infection, such as the perineum or oral cavity.
A patch of anesthesia over the site of erythema is also sometimes described in NF. This is thought to be due to infarction of cutaneous nerves in necrotic subcutaneous fascia and soft tissue [ 28 ]. Necrotizing cellulitis, or hemolytic streptococcal gangrene, generally presents shortly after minor trauma. Patients have findings consistent with cellulitis, including erythema, warmth, and swelling. Unlike other cellulitis severe pain is common.
There may be rapid development of gas distal to the wound and blebs which contain dark serous fluid. The hallmarks of streptococcal myositis are severe local pain and toxemia. Wounds have a foul odor, discoloration, and edema. Patients might develop blebs and gangrene of the overlying skin, although disease progression is characteristically slow. Underlying muscle is not viable and will require excision. One of the most important historical findings associated with clostridial cellulitis is severe pain occurring days after local tissue injury.
Patients subsequently develop skin blebs that contain a reddish-brown, foul-smelling fluid. There is rapid progression of cellulitis over hours and patient is toxic. Crepitus might be noted, but it is not a universal finding. Despite differences, similar clinical profiles are noted. PBSG is a rapidly progressive infection caused by nonhemolytic streptococci in association with hemolytic staphylococci or gram-negative bacilli.
It is most commonly found following abdominal surgeries with infected wound. Clinical presentation is notable for a wound with a central necrotic area that is surrounded by purple, erythematous zones of skin. In addition, necrotic tracts can extend through the underlying tissue, resulting in additional ulcerations at sites distant from the primary lesion.
At first only the scrotum is involved, but if unchecked, the cellulitis spreads until the entire scrotal coverings slough, leaving the testes exposed but healthy.
There are a wide variety of diagnostic tools that have been described and tested to diagnose NF more accurately and expeditiously. Even in the most experienced hands, clinical findings are not accurate enough for diagnosis, and both clinical clues and diagnostic tools should be used in combination to help make an early diagnosis.
Abnormal laboratory findings include an elevated white blood cell WBC count, azotemia, abnormal coagulation profiles, and decreased platelet and fibrinogen levels. Other laboratory findings such as elevated lactate and blood glucose levels, hypocalcemia, hypoalbuminemia, and anemia are also commonly found. The sensitivity of these studies varies, although leukocytosis and hyponatremia have been found to be predictive of necrotizing infection.
Wall et al. Wong et al. The total score had a range of 0—13, and patients were categorized according to the risk of NSTI among 3 groups. This constitutes a great tool for both confirming and discarding NSTI and has the advantage that it is based on laboratory variables that are widely available across different institutions.
Computed tomography and magnetic resonance imaging MRI might be useful in cases where signs are equivocal or diagnosis is in doubt. Asymmetrical fascial thickening, fat stranding, and gas tracking along fascial planes are important imaging findings. In cases of cellulitis, MRI will demonstrate subcutaneous thickening with fluid collection.
However, when there is deep fascia involvement with fluid collection, thickening, and enhancement after contrast administration, necrotizing infections must be considered. According to Schmid et al. It is particularly helpful in the investigation of areas that have disproportionately severe tenderness and when nonspecific signs of sepsis are present. This has been disputed, and other authors have argued that in early cases of NF, MRI might not show fascial involvement [ 35 ].
If clinical suspicion is high, surgeons can opt to explore and perform tissue biopsies rather than delay treatment for imaging studies. In clinically suspicious cases where there is no obvious finding tissue diagnosis may be sought. Fine needle aspiration FNA has been used in the past but is no longer recommended. Incisional biopsy has largely replaced FNA as a more sensitive technique. It can be performed at the bedside under local anesthetic and is advocated in early or equivocal cases.
Standard practice is to take biopsies from a representative area of the infectious process and from the leading edge of any erythematous, edematous, necrotic, or indurated area [ 36 ].
Frozen-section evaluation of an incisional biopsy specimen characteristically reveals necrosis, polymorphonuclear infiltration, microorganisms, vasculitis, and vascular thrombosis located in the superficial fascia, deep dermis, and surrounding adipose tissue. Sparing of epidermis, superficial dermis, and underlying muscle tissue is usually noted.
Gram stain of the tissue sample is also a valuable adjunct to clinical examination and can be performed [ 37 , 38 ]. Primary care physicians have to use clinical judgment to decide which patients who present with evidence of skin inflammation should be hospitalized or receive further evaluation.
The treatment for NSTI involves the principles of treatment for any kind of surgical infection: source control, antimicrobial therapy, support, and monitoring. Patients who have progressive necrotizing infections often deteriorate rapidly.
As soon as the diagnosis of NSTI is suspected, aggressive resuscitation and empiric broad-spectrum antibiotic coverage should be instituted. Septic shock with intravascular volume depletion and shunting in the periphery is an ongoing process at the time of diagnosis. Significant fluid and protein losses occur even before surgical debridement, resulting in inadequate tissue oxygenation.
Early resuscitation with blood products and vasopressins over crystalloids reduce mortality. Main vasopressins used are noradrenaline and dopamine. Patients presenting with multiorgan failure are admitted to surgical intensive care unit SICU. Patients presenting with respiratory failure may require prolonged ventilation and tracheostomy is often required. Renal failure is another frequent complication that might require continuous hemodialysis [ 41 ].
Aggressive nutritional support is mandatory in all patients after debridement. Patients should receive twice their basal caloric requirements orally or parenterally. Nutritional support is associated with fewer complications and lower morbidity and mortality rates [ 42 ]. Pre- and postoperative pain control is also an important part of management and should be individualized for each patient.
Antimicrobial therapy is an adjunct to source control for the treatment of NF. Broad-spectrum antimicrobial therapy should be started early to include coverage for gram-positive, gram-negative, and anaerobic organisms.
Special consideration for Group A Streptococcus and Clostridium species should be taken. Multidrug regimens have also been described, including triple-drug therapy regimens, such as high-dose penicillin, high-dose clindamycin, and a fluoroquinolone or an aminoglycoside for coverage of gram-negative organisms.
Vancomycin, daptomycin, or linezolid should be included in the regimen until methicillin-resistant staphylococcal infection has been excluded. The use of protein synthesis inhibitors, such as clindamycin, may help by inhibiting toxin production, which can be crucial for controlling the inflammatory response in patients with NSTI, particularly in those with clostridial and streptococcal infections.
Prolonged courses of an arbitrary duration are not necessary and may predispose the patient to wound colonization with drug-resistant organisms. In type 2 NF caused by streptococci resulting in streptococcal toxic shock syndrome, intravenous immunoglobulins might play a therapeutic role. A multicentre, randomized controlled trial evaluated the safety and efficacy of intravenous immunoglobulins in streptococcal toxic shock syndrome.
The trial was prematurely stopped because of poor recruitment, but it showed 3. These studies are also controversial and difficult to compare, given the small number of patients and the different methodologies used. It seems reasonable to use intravenous immune globulin in patients with group A streptococcal infection who have developed streptococcal toxic shock syndrome and in those with a high mortality risk advanced age, hypotension, and bacteremia [ 44 ].
Whenever NF has been confirmed surgical debridement is indicated. Unlike cellulitis, these should be red-flag clues for necrotizing fasciitis:. Laboratory indicators of inflammation and end organ dysfunction have been found to be associated with necrotizing soft tissue infections 3 :. A shift change occurred and the patient remained in the ED for several hours prior to transfer to the inpatient unit.
However, the patient was not re-evaluated nor were laboratory results reviewed. Shift change has long been known to be a vulnerable time in Emergency Departments and strategies have been proposed to interrupt errors that might otherwise be propagated.
These strategies include checklists, rounding with off-going physicians, and the use of mnemonics. Finally, the patient presented to the ED pre-diagnosed by the outpatient physician as cellulitis. The emergency physicians may have simply accepted this diagnosis and propagated this error downstream. This cognitive bias or disposition to respond is one of many that may influence decision making in the ED. In this case, a confluence of factors conspired to result in failure to promptly diagnose the necrotizing soft tissue infection.
The emergency physicians missed an opportunity to make a critical diagnosis and put the patient at risk for a worsened outcome. Disclaimer: The cases in this series are very loosely based on an aggregate pool of known patient cases from around the country over the past decade, although the lessons are timeless.
Previous Next. By: Steven Polevoi, MD. Case A year-old male was referred to the ED for evaluation of cellulitis. Additional History He also noted the onset of shaking chills, fevers, and sweats.
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