Dermatology Made Easy is based on the most popular topics from DermNet NZ's vast array of material. The book combines the essential focus of the ‘Made Easy’ book series with the authority and knowledge base of DermNet NZ's unparalleled resources.
Author: Dr Amy Stanway, Dermatology Registrar, Waikato Hospital, Hamilton, New Zealand, 2001. Reviewed and updated by Dr Amanda Oakley Dermatologist, Hamilton, New Zealand; Vanessa Ngan, Staff Writer, June 2014. Further updated by Dr Jannet Gomez, Postgraduate Student in Clinical Dermatology, Queen Mary University, London, United Kingdom, February 2016.
Erysipelas affects the upper dermis and extends into the superficial cutaneous lymphatics. It is also known as St. Anthony's fire, with reference to the intense rash associated with it.
Erysipelas most often affects infants and the elderly, but can affect any age group. Risk factors are similar to those for other forms of cellulitis. They may include:
Unlike cellulitis, almost all erysipelas is caused by Group A beta haemolytic streptococci (Streptococcus pyogenes). Staphylococcus aureus, including methicillin resistant strains (MRSA), Streptococcus pneumoniae, Klebsiella pneumoniae, Yersinia enterocolitica, and Haemophilus influenzae have also been found rarely to cause erysipelas.
Symptoms and signs of erysipelas are usually abrupt in onset and often accompanied by fevers, chills and shivering.
Erysipelas predominantly affects the skin of the lower limbs, but when it involves the face it can have a characteristic butterfly distribution on the cheeks and across the bridge of the nose.
Erysipelas recurs in up to one third of patients due to:
Complications are rare but can include:
Erysipelas is usually diagnosed by the characteristic rash. There is often a history of a relevant injury. Tests may reveal:
MRI and CT are undertaken in case of deep infection.
While signs of general illness resolve within a day or two, the skin changes may take some weeks to resolve completely. No scarring occurs.
Long term preventive treatment with penicillin is often required for recurrent attacks of erysipelas.
Erysipelas recurs in up to one third of patients due to persistence of risk factors and also because erysipelas itself can cause lymphatic damage (hence impaired drainage of toxins) in involved skin which predisposes to further attacks.
If patients have recurrent attacks, long term preventive treatment with penicillin may be considered.
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