Definition of Skin and Soft Tissue Infections in Children
Bacterial skin and soft tissue infections are defined as acute illnesses that are characterized by localized or diffuse skin and subcutaneous infection. This definition includes impetigo, folliculitis and deep subcutaneous infections. Viral causes of skin infections might be implicated in warts or other superficial skin lesions related to molluscum contagiosum.
Epidemiology of Skin and Soft Tissue Infections in Children
Skin and soft tissue infections (SSTIs) are becoming more commonly recognized and diagnosed in children. Some studies link this increase in the incidence of SSTIs to a concomitant increase in the incidence of methicillin-resistant staphylococcus aureus in the community.
The incidence of SSTIs related to staphylococcus aureus alone has doubled in the last decade; therefore, the costs of treating these infections nowadays is estimated to be around 4.22 billion dollars signifying a serious burden on the health-care system.
Another possible cause for the recent increase in the risk of SSTIs could be the increased prevalence of human immunodeficiency virus among children, in addition to the survival of children with impaired immune system due to recent advances in medicine.
Etiology of Skin and Soft Tissue Infections in Children
The most common causes of impetigo are staphylococcus aureus and streptococcus infections. Staphylococcus aureus acquired from the community is becoming resistant to methicillin, which is a serious problem.
Cellulitis and erysipelas are also common nonpurulent SSTIs caused by staphylococcus infections. Purulent SSTIs include furuncle, carbuncle and the formation of abscesses. These conditions are also related to staphylococcus aureus infection. Staph-scalded skin syndrome (SSSS) is a condition that is caused by toxin-producing staphylococcus aureus strains.
Viral etiologies implicated with SSTIs include molluscum contagiosum and the human papilloma viruses. Molluscum contagiosum infections are more common among children aged 1 to 4 years. Warts caused by the human papilloma virus are common in older children and adolescents.
Group A streptococcus is responsible for more invasive SSTIs that might be associated with necrotizing fasciitis. One commonly identified organism of this group is the streptococcus pyogenes.
Clinical Presentation of Skin and Soft Tissue Infections in Children
Simple impetigo presents with localized single or multiple skin lesions that are crusted and brown or honey colored, usually on the face or extremities. It is common in 2 to 5 year old children. A complicated case of impetigo presents with a deeper skin involvement, possibly with a purulent discharge. There are no systemic symptoms in impetigo.
Cellulitis presents with localized swelling, warmth, redness and pain in an area. It involves the dermis and subcutaneous fat and may form abscesses.
Abscesses usually present with a localized swelling or a lump in an inflamed area. Abscesses can be seen in the subcutaneous tissue of an upper or lower limb. Patients with purulent disease are more likely to have a fever and be toxic.
SSSS presents with a painful desquamative skin rash especially around the nose, mouth and anus. The rash can also be seen around flexures. Patients with SSSS might be feverish, develop hypotension, have multisystemic dysfunction or develop sepsis. Therefore, SSSS is considered as a pediatric emergency that needs urgent treatment and adequate fluid replacement therapy.
Acne is another common presentation of Propionibacterium infection or streptococcus superficial skin infections.
Patients with molluscum contagiosum present with self-limited skin lesions that are round and umbilicated. The lesions resemble skin warts. Skin warts caused by the human papilloma virus can occur in the hands or feet, in the genital tract or in the mouth and nasopharynx. Patients presenting with anal or genital warts, who are too young to be involved in sexual activity, should raise suspicions of possible sexual abuse.
Diagnostic Workup for Skin and Soft Tissue Infections in Children
The first and most important step in the evaluation of the patient with SSTIs is to determine whether the child has a deep abscess. Abscesses need to be incised and drained for optimum treatment. After careful examination, most SSTIs do not need any further diagnostic workup.
A complete blood count might be indicated in the evaluation of the patient presenting with severe SSTIs such as SSSS. Leukocytosis might be seen in that case. Electrolyte imbalances are also common with severe SSTIs, such as SSSS.
Culture and sensitivity testing of the infected sites might be indicated in case of failure to respond to typical antibiotic therapy. Methicillin-resistant staphylococcus aureus is becoming more commonly identified in community-acquired cases of impetigo and other SSTIs.
Skin warts or lesions caused by Molluscum contagiosum rarely need further diagnostic workup as they are easy to diagnose clinically. Cases of genital warts that are extensive might warrant the determination of the human papillomavirus type to determine the risk of developing dysplasia or malignant transformation.
Treatment of Skin and Soft Tissue Infections in Children
Nonpurulent SSTIs, such as non-bullous or bullous impetigo, can be treated with topical antibiotics. Possible choices of topical antibiotics include mupirocin, retapamulin and fusidic acid. Fusidic acid is not available in the United States, but has the advantage of being active against propionibacterium acnes.
Patients presenting with moderate SSTIs that affect deeper tissues but do not have any abscesses should be treated with oral or intravenous antibiotics. Possible choices include ceftriaxone and clindamycin. Clindamycin is more likely to be effective against methicillin-resistant staphylococcus aureus, but might be associated with an increased risk of pseudomembranous colitis.
Patients with severe nonpurulent necrotizing fasciitis or SSSS might need surgical intervention and debridement of necrotic tissues. This group of patients should receive intravenous vancomycin plus piperacillin to cover pseudomonas species. This group of patients should undergo culture and sensitivity testing of the infected regions to identify the causative organism and switch to more specific antibiotics with narrow-spectrum.
Patients who are confirmed to have streptococcus pyogenes SSTI should be switched from vancomycin plus piperacillin to penicillin plus clindamycin. A similar protocol should be followed in cases of clostridial necrotizing fasciitis. Necrotizing fasciitis might also be polymicrobial. In that case, vancomycin plus piperacillin should be continued.
Patients with purulent SSTIs, such as abscesses or carbuncles, should first undergo surgical intervention. Incision and drainage relieve symptoms, provide material for culture and sensitivity testing and might be curative.
- Appropriate technique incision and drainage
- Packing is unlikely to help and is painful
- Do not drain with needle
- No antibiotics needed
- Treat with antibiotics if associated cellulitis present (consider MRSA).
Once a sample is collected for culture and sensitivity testing, empirical antibiotic therapy is indicated in this group of patients. Vancomycin or Linezolid are first-line empirical therapies for purulent SSTIs after incision and drainage.
Once the results of the culture and sensitivity tests are available, the main question would be whether the patient has methicillin resistant or sensitive staphylococcus aureus. Patients with purulent SSTIs caused by methicillin-sensitive staphylococcus aureus should be switched to nafcillin. Those who are confirmed to have community acquired methicillin-resistant staphylococcus aureus should continue receiving vancomycin, linezolid or be switched to clindamycin.
Management of molluscum contagiosum and other viral SSTIs is more difficult and the results are usually not as good as with bacterial SSTIs. Cryotherapy and cantharidin are destructive therapy for molluscum contagiosum with good clinical response. Potassium hydroxide has also been used as destructive therapy for skin lesions caused by molluscum contagiosum.
Cryotherapy, paring, excision and the use of cantharidin are also possible options for warts caused by human papillomavirus. Imiquimod has been used as an immune-modulator therapy for the treatment of warts, but should not be used in cases of molluscum contagiosum.
|Cellulitis from bite||Broad coverage with amoxicillin/clavulanate|
|Cellulitis of hand||Admit for IV antibiotics|
|Pilonidal or perirectal abscess||Consider IBD, consult surgeon for evaluation for tract|
|MRSA colonization||Difficult to manage, good hygiene encouraged|