Erysipelas is diagnosed on the basis of clinical presentation and increased inflammatory markers.
Differential diagnostic alternatives include conditions such as suppurative and necrotising skin infections and infections associated with ischaemia or neuropathic ulcer in patients with diabetes.
Penicillin administered either orally or parenterally depending on the severity of the disease and the patient's risk factors is the first-line treatment.
The duration of treatment depends on the response; antimicrobial treatment of 7-14 days is usually sufficient.
In recurrent erysipelas, predisposing factors should be treated and prophylactic treatment started, as necessary.
In general
Erysipelas is generally caused by group A (Streptococcus pyogenes) or group G/C (S. dysgalactiae subsp. equisimilis) beta-haemolytic streptococci (BHS), more rarely by group B (S. agalactiae) streptococci.
There may be a portal of entry, e.g. interdigital tinea pedis, intertrigo, a leg ulcer or other areas of broken skin, such as chronic eczema.
Other local risk factors include lymphoedema, lower limb oedema, obesity, as well as impaired venous and arterial circulation.
Clinical picture
Typical symptoms include a high fever of sudden onset with chills as well as well-demarcated, fiery-red, hot and diffuse erythema and oedema of the skin.
In the majority of cases, erysipelas occurs in the lower leg, ankle or foot (Images 12).
Bilateral erysipelas is very rare (see differential diagnosis).
Erysipelas may also occur in the face (Image 3 ), genital area or the upper extremities (often as a result of deficient lymph circulation).
The patient may experience headache, nausea or general malaise.
The systemic symptoms may sometimes be milder, especially in recurrent or facial erysipelas (Image 4).
Erysipelas may be complicated by skin blisters and haematomas, ulceration, subcutaneous abscesses or sepsis.
Distinguishing between classic erysipelas and sellulitis is difficult, and unnecessary from the viewpoint of treatment.
Differential diagnosis
Infectious diseases
Acute purulent skin infections, such as cellulitis (see below): clinically resembling erysipelas, with purulent discharge, such as a purulent wound infection
Abscess Skin Abscess and Folliculitis: a purulent mass with restricted fluctuation under the skin, pain on palpation
Necrotizing skin infections Severe Infections of the Skin and Soft Tissues: blisters and haematomas on the skin, severe pain, systemic symptoms, poor health status that is getting worse
Foot infections in people with diabetes (associated with ischaemia or a neuropathic wound) Treatment of the Diabetic Foot
Erysipeloid in the hand Erysipeloid: slowly spreading erythema, mild systemic symptoms, animal contact
Other diseases
Stasis dermatitis or other eczemas affecting the legs, for example Lower Leg Dermatitis: usually chronic, possibly with itching, often bilateral, skin lesions due to stasis Venous Insufficiency of the Lower Limbs, such as lipodermatosclerosis
Gouty arthritis Gout and Pseudogout and other noninfectious joint inflammations: erythema in the joint area, restricted mobility, typical clinical picture, and crystal analysis of synovial fluid will lead to the correct diagnosis
Charcot foot in a diabetic patient: arthropathy often in the ankle, usually no systemic symptoms, CRP normal (see Treatment of the Diabetic Foot); MRI will lead to the correct diagnosis
Dependent rubor associated with arteriosclerosis obliterans (ASO): no fever, rubor disappearing when the leg is elevated
Erythema migrans Lyme Borreliosis (LB) in a leg, for example: subacute onset, erythema spreading slowly over several days or weeks, CRP normal
Erythema nodosum: on the legs several raised nodules tender on palpation: see Erythema Nodosum
Relapsing polychondritis (recurrent redness and pain in the area of the cartilage of the external ear; the ear lobe remains normal)
Workup
CRP and B-Leuc may be normal at the onset of symptoms; CRP remaining normal for a few days strongly suggests something other than erysipelas.
Purulent skin infection: bacterial culture can be performed as necessary for sensitivity testing (to exclude MRSA, for example)
Blood bacterial culture should be performed for hospitalized patients particularly if the diagnosis is uncertain or if there are risk factors
Treatment
For treatment, it is important to differentiate between genuine erysipelas and purulent (wound infection, abscess, skin penetrating injury) and necrotizing skin infections.
The dosage of antimicrobial therapy is defined according to the severity of the infection, not the patient's weight.
Oral administration can be used from the very beginning if the patient is in a good general condition.
1-1.5 million units penicillin V 3-4 times daily p.o.
If the patient's condition requires hospital treatment, penicillin should be given parenterally at first.
2-4 million units penicillin G every 4-6 hours i.v. (for practical reasons 5 million units 4 times daily i.v. can be used) or
1.5 million units procaine penicillin 1-2 times daily i.m.; can be given as single daily doses to facilitate treatment at home.
Switching over to oral medication (1-1.5 million units penicillin V 3-4 times daily) is possible once the local symptoms of the infection have started to subside and the patient has been afebrile for at least one day (24 hours). Usually, inflammatory markers have started to improve at this point as well.
A total period of treatment of 7-14 days is usually sufficient. If there has been a consistent response to treatment, antimicrobial medication can often be withdrawn even if there is still slight erythema and oedema.
If the response is slow, in high-risk patients and in the case of recurrent erysipelas, the total duration of antimicrobial treatment can be extended to 3 weeks.
Streptococci found in blood culture usually require 7-10 days of intravenous antimicrobial treatment.
In addition to antimicrobial treatment, symptoms can in the initial phase be alleviated by moist compresses applied 2-3 times daily, for example.
For patients hypersensitive to penicillin:
cephalosporins (if there has been no anaphylactic reaction to penicillin): 1.5 g cefuroxime three times daily i.v., followed by 500-1 000 mg cephalexin 3-4 times daily p.o. or
clindamycin (first 600 mg 3-4 times daily i.v. and then 600-1 800 mg daily p.o., divided into 3-4 doses)
If Staph. aureus infection is suspected (wound infection, abscess, skin penetrating injury), it should be covered when choosing antimicrobial therapy.
Cellulitis
Cellulitis resembles erysipelas but the inflamed area extends deeper into the adipose tissue with ulcerations, suppurative areas and abscesses.
There may also be cellulitis spreading from an abscess or a purulent or surgical wound infection.
If the skin infection was purulent or clearly ulcerative from the very beginning, antimicrobial treatment must also cover Staph. aureus (see below).
If the patient is in a good general condition, oral antimicrobial treatment may be sufficient, the duration of treatment being the same as for erysipelas.
For patients requiring hospital treatment, intravenous treatment will be needed at first.
2 000 mg cloxacillin 4-6 times daily i.v. or 1.5 g cefuroxime 3 times daily i.v. or 600 mg clindamycin 3-4 times daily i.v. (if the patient has a history of anaphylactic reaction to penicillin or is allergic to cephalosporin)
As the situation calms down, treatment can be continued orally: 500-750 mg floxacillin 3-4 times daily p.o., 500 mg cephalexin 3-4 times daily p.o. or 600-1 800 mg clindamycin daily divided into 3-4 doses
Antimicrobial treatment of a chronic wound is indicated only if there are clear signs of infection.
In the case of a septic clinical picture, intravenous clindamycin may be added to the therapy. In MRSA carriers, vancomycin is included in the initial therapy (do not hesitate to consult an infectious diseases specialist).
Recurrent erysipelas
If erysipelas recurs frequently, long-term prophylactic therapy needs to be considered. Prophylactic antimicrobial treatment should be considered after the first recurrence, considering the duration of treatment case by case. Typically, prophylactic treatment is given for 1 year, during which any risk factors should also be treated, but it often needs to be continued for a longer time.
The dose should be tailored individually depending on how quickly the symptoms recur.
Patients with penicillin allergy (who have not had anaphylaxis) can usually take cephalosporins, such as 500 mg cephalexin 1-2 times daily.
Before starting prophylactic treatment, it should be confirmed that the patient has recurrent erysipelas and not some other condition, such as stasis dermatitis (see differential diagnosis).
Any predisposing factors should be treated, such as chronic oedema (venous insufficiency, lymphoedema), skin injuries (e.g. interdigital tinea pedis, intertrigo, unsuitable shoes) or overweight.
If erysipelas recurs it is important to identify and treat any portals of entry for infection and advise the patient to guard against new exposure (e.g. unsuitable footwear).
In patients with leg oedema, it is particularly important to make sure that compression therapy is used (compression stockings, intermittent pneumatic compression, and, in severe lymphoedema, manual lymph drainage).
Necrotising infection
The treatment of necrotising infection usually consists of surgical management combined with broad spectrum intravenous antimicrobials.
Warning signs of a necrotising infection include intense pain, haematomas and vesicle formation on the skin, intense swelling extending beyond the skin lesion, loss of sensation on the skin, severe systemic symptoms and sepsis.
References
Oh CC, Ko HC, Lee HY et al. Antibiotic prophylaxis for preventing recurrent cellulitis: a systematic review and meta-analysis. J Infect 2014;69(1):26-34. [PubMed]
Kwak YG, Choi SH, Kim T et al. Clinical Guidelines for the Antibiotic Treatment for Community-Acquired Skin and Soft Tissue Infection. Infect Chemother 2017;49(4):301-325. [PubMed]