Information
Editors
Impetigo and other Pyoderma
Essentials
- Impetigo spreads easily in the family, day-care centre and school.
- Remember the possibility of post-infectious glomerulonephritis in streptococcal impetigo.
Clinical features
- Children are most commonly affected.
- Streptococcal infection typically makes crusts or small ulcerations; staphylococcal infection tends to make blisters (pictures 1 2).
- "Pemphigus neonatorum" (picture 3) in infants is actually impetigo. The infection is caused by Staphylococcus aureus phage type II.
- The crusts usually appear in the surroundings of the nostrils (picture 4), on the chin (picture 5), and generally on the face (pictures 67).
- Thick crusts are characteristic.
Differential diagnosis
- Primary herpes simplex infection may resemble impetigo.
- Ringworm (tinea corporis)
- If impetigo tends to recur in the scalp and neck consider the possibility of head lice.
Causative agents
- Staphylococcus aureus
- Group A beta-haemolytic streptococci (picture 8)
- Eczema (picture 9) may predispose the skin to impetigo.
- The infection usually spreads by autoinoculation.
- Recurrences are often caused by bacteria remaining in the nostrils from where they are re-spread by fingering of the nose.
Treatment
- Treatment is started on the basis of the clinical presentation.
- If the disease is confined to a small area the treatment consists of soaking the crusts so that they are detached, and applying an antimicrobial ointment (fusidic acid Interventions for Impetigo or a combination of neomycin and bacitracin).
- If the disease is more widespread (> 6 cm2 ) use a systemic antimicrobial effective against S. aureus, primarily cephalexin Systemic Antibiotics in the Treatment of Impetigo in Children or flucloxacillin 750-1 000 mg 3 times daily. Duration of treatment is usually 7-10 days. Patients with cephalosporin allergy can be treated with clindamycin.
- If the patient has eczema a topical preparation containing a glucocorticoid and an antimicrobial agent should be used together with systemic antimicrobials until the skin is intact.
- Do not forget further treatment of the eczema.
- The most common reasons for poor response to treatment
- The diagnosis is incorrect. The patient has scabies, lice, or ringworm.
- The crusts have not been soaked and removed. The bacteria can survive under crusts.
- The underlying eczema has not been treated.
- The nostrils serve as reservoir for bacteria (apply neomycin-bacitracin or fusidic acid ointment into the nostrils. Mupirocin should not be used for this disease as its use should be limited to the eradication of methicillin-resistant Staphylococcus aureus).