If there is a history of river or sea water exposure, treatment choices should be discussed with a microbiologist.

First line:

Flucloxacillin oral 500mg 6 hourly

If true penicillin / beta-lactam allergy or suspected MRSA:

Doxycycline oral 200mg stat, then 100mg once daily

N.B. In pregnant patients, doxycycline is contraindicated. See here for an alternative option in penicillin allergic pregnant patients. If pregnant with suspected MRSA, discuss with a microbiologist.

Outpatient parenteral antimicrobials (OPAT):

OPAT is available for lower limb cellulitis and can be accessed via the medical ANP teams in both Combined Assessment Unit in NHS A&A.

Follow this OPAT algorithm.

• Cellulitis presents as an area of skin which is acutely red, hot, tender and swollen; it is not uncommon for blisters or bullae to develop.
• The leg is the most common site and presentation is almost exclusively unilateral. Chronic venous eczema can mimic the appearance of cellulitis and be mislabelled as "bilateral cellulitis".
• Minor breaks in the skin can act as portal of entry.

If the patient is not febrile and has no underlying chronic diseases or immunocompromise, cellulitis can be managed as an outpatient or in primary care.

Refer any patient in primary care with the following for IV treatment:

• comorbidities that may affect wound healing, e.g. diabetes
• frail or elderly patients
• any patient that appears systemically unwell

Take a swab for bacterial culture and sensitivity from any possible portal of entry or areas of broken down skin. Review any culture results and ensure that an appropriate antibiotic has been prescribed.

General advice: Draw around the perimeter of the affected area with a permanent marker pen for future comparison. Advise rest and elevation of the affected limb.