Impetigo Flashcards
What is impetigo?
Impetigo is a common acute superficial bacterial skin infection characterised by pustules and honey-coloured crusted erosions (‘school sores’).
The word ‘impetiginisation’ is used for superficial secondary infection of a wound or other skin condition. Ulcerated impetigo is called ecthyma.
Who is commonly affected by impetigo?
Impetigo is most common in children (especially boys), but may also affect adults if they have low immunity to the bacteria. It is prevalent worldwide. Peak onset is during summer, and it is more prevalent in developing countries.
Are the majority of cases of impetigo bullous or non-bullous?
Non-bullous impetigo- accounts for the majority of cases (about 70%).
How is impetigo transmitted?
Transmission of impetigo occurs directly through close contact with an infected person or indirectly via contaminated objects such as toys, clothing, or towels.
What are the risk factors for impetigo?
The following factors predispose to impetigo.
- Atopic dermatitis
- Scabies
- Skin trauma: chickenpox, insect bite, abrasion, laceration, thermal burn, dermatitis and surgical wound
What causes non-bullous impetigo?
Non-bullous impetigo is caused by Staphylococcus aureus, Streptococcus pyogenes or a combination of both.
What causes bullous impetigo?
Bullous impetigo is caused by Staphylococcus aureus.
Bullae form when exfoliative toxins produced by S. aureus cause loss of cell adhesion in the superficial epidermis.
What are the clinical features of impetigo?
Primary impetigo mainly affects exposed areas such as the face and hands, but may also affect other body sites. It presents with single or multiple, irregular crops of irritable superficial plaques. These extend as they heal, forming annular or arcuate lesions.
Although many children are otherwise well, lymphadenopathy, mild fever and malaise may occur.
Briefly differentiate between the clinical features of nonbullous impetigo, ecthyma and bullous impetigo
Nonbullous impetigo
Nonbullous impetigo starts as a pink macule that evolves into a vesicle or pustule and then into erosions with a honey-coloured crust. Untreated impetigo usually resolves within 2 to 4 weeks without scarring.
Ecthyma
Ecthyma starts as nonbullous impetigo but develops into a punched-out necrotic ulcer that heals slowly, leaving a scar.
Bullous impetigo
Bullous impetigo presents with small vesicles that evolve into flaccid transparent bullae. It heals without scarring.
What are the complications of impetigo?
- Soft tissue infection
- Staphylococcal scalded skin syndrome
- Toxic shock syndrome
- Post-streptococcal glomerulonephritis
- Rheumatic fever
How is impetigo diagnosed?
Impetigo is usually diagnosed clinically but can be confirmed by bacterial swabs sent for microscopy (gram-positive cocci are observed), culture, and sensitivity.
A blood count may reveal an elevated white cell count due to increased neutrophils when impetigo is widespread.
Skin biopsy is rarely necessary. The histological features of impetigo are characteristic
Briefly describe the general treatment methods for impetigo
Cleanse the wound; use moist soaks to remove crusts gently.
Apply antiseptic 2–3 times daily for five days (povidone-iodine, hydrogen peroxide 1% cream, chlorhexidine, superoxidised solutionand others).
Cover the affected areas.
What advice should be given to a patient with impetigo?
Advise the person about good hygiene measures to aid healing and reduce the spread of impetigo to other areas of the body and to other people. Recommend that the person:
- Washes affected areas with soap and water
- Washes their hands regularly, in particular after touching a patch of impetigo
- Avoids scratching affected areas
- Avoids sharing towels, face cloths, and other personal care products and thoroughly cleans potentially contaminated toys and play equipment
How is localised non-bullous impetigo treated?
Consider prescribing hydrogen peroxide 1% cream for people who are not systemically unwell or at a high risk of complications.
If this is unsuitable, prescribe a short course (5 days) of a topical antibiotic (e.g. fusidic acid 2%).
How is widespread non-bullous impetigo treated?
Offer a short course of a topical or oral antibiotic for people who are are not systemically unwell or at high risk of complications.
Prescribe topical fusidic acid 2%.
If this is not suitable, prescribe oral flucloxacillin (5 days) for both adults and children. If pencillin allergic, prescribe clarithromycin.
Do not offer a combination treatment with a topical and oral antibiotic.
What is shown in the image?
Impetigo
What is shown in the image?
Impetigo
What type of impetigo is seen?
Bullous impetigo
What type of impetigo is seen?
Bullous impetigo
What type of impetigo is seen?
Non-bullous impetigo
What type of impetigo is seen?
Non-bullous impetigo
What type of impetigo is seen?
Ecthyma
What type of impetigo is seen?
Ecthyma
Briefly recap the 3 different types of impetigo
