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Cellulitis & Erysipelas: It’s Red, It’s Swollen, It’s Tender!

What Are Cellulitis and Erysipelas?

Cellulitis and erysipelas are two types of skin infections most commonly caused by the species of bacteria known as Streptococcus. This bacteria thrives on many surfaces and even on the skin of humans. The infection may spread and cause widespread inflammation in the affected area of the body if left untreated. Hit the books about this condition in relation to our sample pediatric case!

Left Leg, Left for Dead

Take, for example, the case of Ms. W, a four-year-old per-schooler who initially presented with symptoms of swelling of her left lower leg. Two weeks prior to admission, Ms. W’s mother reported that she noticed a small puncture wound on the leg, but since it was too small, she disregarded it and barely paid attention to it. She thought that it was nothing serious, since the child was not complaining about it at all. She was unable to recall where exactly her daughter got the wound but related that the leg was probably scratched while she was playing on their lawn. The wound was left alone and untreated.

There were no complaints noted by Ms. W at first; nonetheless, over a span of two weeks, she developed fever, vomiting, and loss of appetite. The area of redness had spread wider and was characterized similar to that of a map with clear-cut borders. They tried to do first aid treatment at home by addressing the fever and letting the patient rest. The said symptoms persisted, so they opted to seek consultation.

When the Swollen Ran the Show

The case presentation of the patient is an apparent infection of the left lower extremity, exacerbated over a duration of two weeks and eventually culminated in an acute swelling necessitating admission. Skin infections are commonly described based on the depth of the skin involvement. There are several common causes in the pediatric population group alone.

The initial step in the diagnosis of the patient involves an assessment of the lesion’s localization. It is seen that the patient initially manifested lesions on her left lower extremity. This is reported to be aggravated by scratching of the patient. Bacterial skin infections may be initially considered based on the epidemiology and the initial appearance. The most common types are caused by Staphylococcus and Streptococcus spp.; depending on their degree of skin structure involvement, they are labelled as impetigo, folliculitis, furuncle, carbuncle, erysipelas, scarlet fever, and staphylococcal skin infections being the most common. The initial approach includes these types of skin infections due to the presence in the skin of normal flora, and as described by the patient, it was initially of a lesser degree and was just aggravated over a 14-day period.

Cardinal signs of inflammation

Cardinal signs of inflammation

Know Thy Enemy: Cellulitis vs. Erysipelas

The presence of bacterial skin infection is usually heralded by common signs such as erythema (redness), warmth, pain, tenderness, swelling, induration, crusting, and drainage. The condition can be further determined based on the localization, spread, purple discoloration, skin necrosis, and blistering. These are more commonly known as the cardinal signs of inflammation, which is not only present in bacterial infections but also in any other cause of inflammation as well.

The presence of bacterial skin infection is usually secondary to the development of the lesion after invasion of the normal flora in the initial break in the skin. This is predisposed by factors such as temperature, humidity, poor hygiene, and crowding in the patient’s living conditions. In the case of the patient, the untreated puncture wound caught while playing was the nidus where the bacteria thrived.

Erysipelas and Cellulitis are caused by a subgroup of a bacteria species known as the beta hemolytic streptococci (usually by the species Streptococcs pyogenes). Both diseases almost have the same manifestation and are only differentiated based on the structure involved and the layer of skin invasion. They also present with localized signs of inflammation, which may be accompanied by lymphadenitis (swelling of the lymph channels).

Comparison Table


Area Commonly Affected

Leg, Face

Leg, Abdomen, Orbit, Cheeks

Causative Pathogen

Usually Beta Hemolytic Streptococcus spp.

Usually Beta Hemolytic Streptococcus spp.


Inflammation but With Clear Borders, Raised Above Skin

Inflamed, but May Not Have Clear Borders

Area Affected

Superficial Skin Layers

Deeper Skin/Tissue Laters




Comparison of normal leg vs. leg with cellulitis

Comparison of normal leg vs. leg with cellulitis

Erysipelas of lower leg with clear-cut borders

Erysipelas of lower leg with clear-cut borders

And the Winner Is...

In the case presented, erysipelas is favored over cellulitis since the lesion is more characteristic of a superficial rather than a deeper infection. The typical form presents as an area of inflammation, with a slightly raised skin with clear demarcation between the infected and the uninfected skin. This is opposed to the deep-seated infection which has no clear-cut borders and less elevation of the skin surface.

The pathogenesis of erysipelas usually involves an initial break in the skin barrier, allowing the infective organism to access the superficial skin layer. This may include abrasions, parasitic infections, puncture wounds, or even iatrogenic causes of disruption of the skin layers. The most common cause includes the Group B Streptococci; rarely Staphylococcus aureus may be involved.

The condition may also contribute to the development of more complications later in the course of the disease if not treated adequately. Local inflammation may predispose to more lesions such as bullae, abscesses, hemorrhagic lesions, and necrosis.

Some studies suggest that erysipelas of the legs are becoming more common than that of the face; it has also an increased recurrence rate since the pathogen is sometimes harbored in the superficial tissues. The patient’s mother also reported an infection on the left leg that the happened 10 months prior to admission with similar presenting manifestations. In one large study for patients with erysipelas, it was seen that lymphedema is the single most important factor in recurrence; this is also predisposed by the presence of chronic impairment in the host’s defenses.

"Streptococcus pyogenes"

"Streptococcus pyogenes"

Supporting Laboratory Tests

The use of skin swabbing on the affected area or drainage of the lesion may be done to analyze the specimen based on gram stain and culture. This will ensure the isolation of the offending pathogen, leading to the proper use of antimicrobials.

A complete blood count may be obtained to check the degree of systemic involvement. Culture of blood is necessary in cases when the patient will develop signs of septicemia and treatment after initial antibiotic therapy fails.

Treatment for the Swollen

The main goal of treatment is to eradicate the initial infection prevent its spread. Empirical antimicrobial therapy is needed, and its pharmacokinetic properties are dependent on the localization of the lesion. In the case of the patient, several choices antibiotics may be used as initial management:

  • Penicillin: It is regarded as the drug of choice for this type of infection. Initial management for gram-positive organisms, but may have treatment failure due to the development of common resistant strain, commonly seen even in the communities.
  • Cephalosporins: has good spectrum of activity; the third generation may cover both gram-positive and gram-negative organisms. Furthermore, it was noted that it has good pharmacokinetic and tolerability profiles, which confer an advantage
  • Atipyretic: Adjunct symptomatic treatment with Paracetamol may be given to alleviate the effects of systemic inflammatory response to the patient

She Came Out Running

After less than a week of antibiotic treatment, Ms. W has shown significant signs of improvement. The fever and tenderness over the site have gradually decreased. The redness and inflammation subsided thereafter. She was discharged from the hospital with imperative instructions on how to continue her medications and was given health education on the importance of wound cleaning.


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This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2015 LM Gutierrez


LM Gutierrez (author) on January 07, 2015:

That's exactly the type of complication that could have happened should this case was not treated earlier! The Patient's leg has progressed wherein the area of redness has reached from the edge of the kneecaps down the ankles. The parent reported that it has picked-up its speed of expansion only affecting the middle part of the calf 2 days prior to admission. Also, the patient was already having spikes of fever and vomiting upon admission. It's really a little bit alarming how simple unrecognized wounds and small bites (insect bites in many cases of pediatric patients) can lead to such problems/ complications.

Thanks for sharing your personal experience on this Austinsar!

Lela from Somewhere near the heart of Texas on January 07, 2015:

Just this summer I had cellulitis and septicemia from a cat bite! The bacteria was Staph Epi and it was anaerobic. I nearly died! My hand had the cellulitis, but my kidneys and blood stream carried the Staph. I had near immediate growth in both aerobic and anaerobic blood culture bottles. My hand, where the cat bite was, resembled the leg in your photo. I had four days of IV antibiotics and am now recovered. But this is something to warn everyone about.