2.3 0.5 CONTACT HOURS CONTACT HOURS Uncovering common bacterial skin infections Abstract: The four most common bacterial skin infections are impetigo, erysipelas, cellulitis, and folliculitis. This article summarizes current information about the etiology, clinical presentation, diagnosis, prevention, treatment, and implications for primary care practice needed to effectively diagnose and treat common bacterial skin infections. By Daria Napierkowski, DNP, RN, ANP-BC, CNE acterial skin infections are commonly seen by negative organisms.3 Skin infections increased to the sev- nurse practitioners (NPs) in primary care practice enth most common condition among hospitalized chil- B as well as in the hospital. Bacterial skin infections dren in 2009, whereas it was the 13th most common usually result from breakage of the skin, can be considered condition in 2000.4 The rate of skin infection hospitaliza- mild if they are superfi cial, and/or can result in a severe tions overall has increased 29% from 2000 to 2004, while infection: necrotizing fasciitis. Necrotizing skin infections conditions for other infectious diseases, such as infectious are rare–yet severe–and cause body tissue to die.1,2 The most pneumonia, have not increased.5 These rates are consistent common skin infections seen by the NP in primary care with increasing hospitalizations for MRSA bacterial skin practice are impetigo, erysipelas, cellulitis, and folliculitis.3 infections.5 The most common organisms seen in bacterial skin Diagnosis of a bacterial skin infection needs careful infections are streptococci, Staphylococcus aureus, and consideration because other conditions such as thrombo- methicillin-resistant Staphylococcus aureus (MRSA).2 Skin phlebitis, deep vein thrombosis, medication reactions, and infections may have a negative impact on the patient’s gout can mimic the erythema, swelling, warmth, and tender- quality of life and warrant a discerning diagnosis and ness of a skin infection.2 A comprehensive patient history is prompt treatment. essential to rule out other diagnoses. Skin infections com- Patients with diabetes and immunodefi ciencies are monly come with a complaint of a prior break in the skin: more susceptible to skin infections caused by gram- insect bite, animal bite, puncture wound, or laceration. Key words: bacterial skin infections, cellulitis, erysipelas, folliculitis, impetigo 30 The Nurse Practitioner • Vol. 38, No. 3 www.tnpj.com Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Photo by Chris Fertnig/istockphoto.com © www.tnpj.com The Nurse Practitioner • March 2013 31 Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Uncovering common bacterial skin infections Questions concerning the patient’s comorbid conditions hospitalized if the infection does not have declining should be carefully explored. The wound should be exam- symptoms in 72 hours or if the patient develops a fever, has ined for areas of erythema, swelling, exudate, necrosis, increasing pain at the site, tissue necrosis, or has an immu- crepitus, and color changes of the skin. Associated symptoms nocompromised state.2 include fever, increased heart rate, decreased BP, or enlarged lymph nodes close to the site of the wound (which should ■ Impetigo be carefully monitored). Most common bacterial skin infec- Etiology: The organisms responsible for impetigo are S. tions do not require lab assessment except if the patient has aureus (which lives on the skin and mucous membranes) a comorbid disease or severe infection. A baseline complete and Streptococcus pyogenes commonly found in the blood count, chemistry, and C-reactive protein can be gastrointestinal system, genitourinary system, and respira- obtained with widespread infections.2 Cultures, including tory system. Both organisms are classifi ed as gram-positive blood cultures, are cost-effective in patients who are im- cocci and are facultative anaerobes that can survive at low munocompromised, especially if the infection becomes levels of oxygenation. S. aureus causes an infection when severe and guides antibiotic therapy.2 Patients should be skin is broken, whereas S. pyogenes produces enzymes that facilitate an infection. S. pyogenes can be found in asymp- Bullous impetigo with crust formation tomatic carriers in the general population. The nares can also be colonized with S. aureus, and colonization with MRSA should be considered.6 Impetigo is a bacterial skin infection commonly seen in children–especially preschool children. Children and adults who play contact sports (wrestling, football, rugby, and basketball) are more sus- ceptible to impetigo, although impetigo is not as common in adults.7 Factors that can lead to an outbreak of impetigo in communities or institutions include a warm, humid climate, overcrowded conditions, and patients with poor hygiene or nonintact skin. Clinical presentation: There are two classifi cations of impetigo: bullous and nonbullous. Bullous impetigo pres- ents as fl uid-fi lled bulla containing a serous yellow fl uid, and when it ruptures, it leaves a partially-denuded area Source: Goodheart HP. Goodheart’s Photoguide of Common Skin Disorders. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003. with a ring of bulla remaining (see Bullous impetigo with crust formation). Bullous impetigo is less common, more severe, and has signifi cant mortality in infants. Nonbullous Impetigo contagiosa impetigo, also referred to as impetigo contagiosa, initially presents as small vesicles or pustules with the characteris- The photo shows a child with impetigo in the nasal area 3 with the characteristic honey-colored crusts. tic areas of honey-colored crust (see Impetigo contagiosa). Impetigo is commonly seen in intertriginous areas, the face, and extremities where there is a break in the skin. Impetigo can occur in more than one area, and a mixture of the two (bullous and nonbullous) can occur. Both forms are caused by S. aureus; however, in the nonbullous form, streptococcus is usually involved. Lymphadenopathy and an elevated white blood cell count are often seen in the acute stages of impetigo.8 Impetigo does not commonly cause scarring because it does not ulcerate and is usually confi ned to the epidermis; however, lesions can leave areas of depigmentation. Ecthyma is an ulcerative form of im- petigo that extends deeper into the skin and is typically 9 Source: Rubin R., Strayer D, Eds. Rubin’s Pathology: Clinicopathologic Foun- found on the legs and forearms. dations of Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; Diagnosis: Diagnosis of impetigo can be made by a 2008:1037. culture of the infected site or is based on the following 32 The Nurse Practitioner • Vol. 38, No. 3 www.tnpj.com Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Uncovering common bacterial skin infections presenting infection characteristics: serous yellow-fi lled bulla or small vesicles with honey-colored crusting. Other Erysipelas of the face skin infections should be considered in the differential A patient with a facial rash that is salmon color and diagnosis, such as herpes, chicken pox, contact dermatitis painful to touch. with secondary infection, tinea corporis, or an allergic reac- tion.7 A thorough patient history can rule out other skin infections or conditions. Prevention: Impetigo is very contagious, can spread to other areas of the body, and is easily passed by direct con- tact. Children in day-care often pass the bacteria to other children and the adults caring for them. Heat and humid- ity, as well as areas of cracked skin, can increase the chanc- es of contracting impetigo. A viral infection with exudate from the nose can impair skin integrity under the nose and is a common site of impetigo. Children and adult caregivers should wash their hands often, especially after touching infected skin. Children should not be in contact with other children until 48 hours after initial treatment. Items such as towels and blankets should not be shared Source: Barankin B. The Barankin Dermatology Collection. Baltimore, MD: among children, and all toys need to be thoroughly washed Lippincott Williams & Wilkins; 2003. on a daily basis. Treatment: The extent of the infection will guide treat- options for patients with a penicillin allergy or MRSA infec- ment. Areas of infection should be washed with soap and tion include clindamycin.9 Erythromycin is no longer used water daily, and towels should also be washed daily and not because of resistant strains of S. aureus.9 shared with others. Crusted areas can be soaked two or three Implications for practice: Impetigo is a common bacte- times a day with a solution of a half cup of vinegar in a liter rial skin infection that can easily be spread from person-to- of warm water (gently removing the crust).9 Mupirocin person. Strict hand washing is essential in the community, ointment 2% can be prescribed for topical use to be applied especially in areas where children congregate and play. Adult in a thin layer to the affected site three times a day.10 Other caregivers must be taught proper hand washing and care of treatments (for instance, bacitracin and neomycin) have not all toys and equipment in a day-care situation or school. been found to be as effective as mupirocin.9 Additionally, Personal items should be marked with the child’s name and the initial use of mupirocin can help prevent the develop- are not to be shared. Caregivers should be taught to ment of MRSA.3 The area can be covered with loose-fi tting immediately notify parents of suspicious lesions. gauze if needed. Treatment should extend until all areas are free from infection and a few days following; the usual treat- ■ Erysipelas (noncomplicated cellulitis) ment is 10 days, and unused ointment should be discarded.9 Etiology: The organism that causes erysipelas is beta- Mupirocin should be used cautiously in patients with im- hemolytic S. pyogenes and, occasionally, S. aureus that paired renal function and in those who are breastfeeding enter the skin after trauma or a break in the skin.