Symptoms
Impetigo is a highly contagious superficial skin infection observed in two main clinical manifestations. It mainly affects children between 2-6 years of age and infants.In small vesicular (non-bullous) impetigo contagiosa, reddened patches appear that rapidly develop into small vesicles and pustules, break open, and release a cloudy yellowish fluid. This leads to the typical golden / honey yellow crusted lesions surrounded by redness. The lesions may itch, flow into each other, and be surrounded by satellite lesions. The region around the mouth and nose and the nostrils are most commonly affected. There may also be swelling of the lymph nodes and the disease may spread. Large blistered bullous impetigo often occurs in infants in skin folds. A thin-walled, flaccid blister forms from the initial redness and contains a clear, yellowish fluid that may be clouded with pus. After disintegration, large, circular, superficial erosions with thin brownish crusts and blister remnants at the edges remain after 1-2 days. Systemic accompanying symptoms such as fever, weakness, and diarrhea may occur. The course varies: lesions often heal on their own, even without treatment, but may spread and persist for prolonged periods. Rare complications include cellulitis and glomerulonephritis. Lesions usually heal without scarring.
Causes
The cause of the symptoms is a bacterial skin infection with staphylococci and/or streptococci. Bullous impetigo is always caused by. The bacteria produce tissue-dissolving toxins that slough off the top layers of the epidermis, causing a blister. Non-bullous impetigo is caused by staphylococci and/or β-hemolytic group A streptococci. However, infection with staphylococci is more common.
Transmission
Infection is transmitted either directly or indirectly from person to person, from asymptomatic carriers, or via surfaces and objects. Autoinfection is often assumed: In many affected individuals, a staphylococcal reservoir is found in the nostril, from which the bacteria are carried to easily injured or pre-damaged skin (e.g., insect bites, minor skin injuries, minor scratches, eczema, cold sores, abrasions, burns, bites, tears in the corners of the mouth). This complication is also called secondary impetigo. The throat (streptococcal angina) or existing lesions can also be such a focus. The bacteria also occur as part of the natural skin flora. The disease is very contagious and can spread in the family, day care center, kindergarten or school.
Risk factors
Risk factors include contact with infected individuals, close skin contact during sports, atopy, atopic dermatitis (frequent carrier of staphylococci, pre-damaged skin), diabetes mellitus, intravenous drug abuse, dialysis, a warm and humid climate (warm season), poor hygiene, and a staphylococcal reservoir in the nose.
Diagnosis
Diagnosis is made under medical treatment on the basis of the patient’s history, clinical presentation, and laboratory chemistry methods (smear, culture, Gram stain). Possible differential diagnoses include numerous skin diseases (see, e.g., Brown et al., 2003).
Nonpharmacologic treatment
Wound treatment: soften and detach the crust with moist dressings, physiologic saline, and disinfectants. Good hygiene must be maintained during treatment (hand washing, hand disinfection) to avoid infection. If possible, the lesions should not be scratched or touched.
Drug treatment
For a mild course, topical antibiotics are as effective as oral antibiotics. Fusidic acid (Fucidin) and mupirocin (Bactroban) are used. Of mupirocin, a nasal ointment is also available to eliminate the reservoir in the nose. In 2009, retapamulin was approved in many countries and can also be used for treatment. Bacitracin, polymyxin B, and neomycin are considered less appropriate. Gentamicin (Garamycin) is also controversial. Adverse effects include local reactions, and potential resistance is a concern. In the USA, ozenoxacin was additionally released in 2017.In a severe course, antibiotics are also administered systemically. In this case, more possible adverse effects must be accepted. Among others, flucloxacillin, amoxicillin + clavulanic acid, cephalosporins, macrolides and clindamycin are used. How effective disinfectants such as povidione-iodine or chlorhexidine are for treatment is controversial. They may be used to soften the crusts. Preparations containing tea tree oil seem to be good for treatment. We have no data on tolerability in infants or young children. Gentianaviolet, clioquinol, and other antiseptics are mentioned in the literature as alternatives to antibiotics.
