Upper Limb Cellulitis

Upper limb cellulitis is acute bacterial infection of the dermis and subcutaneous tissue of the arm or forearm, caused mainly by beta haemolytic streptococci and Staphylococcus aureus. It is less common than lower limb cellulitis but carries specific risks in lymphoedema and drug injection.

• Risk factors: lymphoedema after axillary lymph node clearance or radiotherapy, injection drug use, wounds, bites, burns, intravenous cannulae, eczema, diabetes, immunosuppression.
• Community acquired MRSA is relevant in injectors and closed communities.

Warm, red, swollen, tender arm with fever, chills and malaise; lymphangitic streaking and tender axillary nodes.

• Differential diagnosis: deep vein thrombosis of the upper limb, thrombophlebitis, contact dermatitis, gout, septic arthritis, abscess, necrotising fasciitis, extravasation injury, insect bite, lymphoedema without infection, cutaneous anthrax.
• Complications: abscess, necrotising fasciitis, bacteraemia and sepsis, septic arthritis, osteomyelitis, endocarditis (injectors), recurrent infection and lymphoedema, compartment syndrome.

Clinical.

• Full blood count, CRP, blood cultures if febrile; wound swab.
• Ultrasound for abscess or venous thrombosis; radiograph or MRI if bone or joint involvement is suspected.
• HIV, hepatitis B and C tests in injection drug users; glucose.

Antibiotics, elevation and attention to the portal of entry.

• Supportive: elevate the arm on pillows, analgesia (paracetamol 1 g, ibuprofen 400 mg), mark the border, remove rings and constricting items, gentle active movement, avoid venepuncture, blood pressure cuffs and injections in a lymphoedematous arm.
• Pharmacological: flucloxacillin 500 mg to 1 g four times daily for 5 to 7 days (extend to 10 to 14 days if slow response); penicillin allergy: clindamycin 300 to 450 mg three times daily, or doxycycline 100 mg twice daily. Severe or systemic: flucloxacillin 1 to 2 g IV every 6 hours with benzylpenicillin 1.2 g IV every 6 hours; MRSA risk or injectors: vancomycin 15 to 20 mg/kg IV every 12 hours. Tetanus toxoid if indicated. Recurrent cellulitis in lymphoedema: phenoxymethylpenicillin 250 to 500 mg twice daily for 6 to 12 months or benzathine benzylpenicillin 1.2 million units IM every 3 to 4 weeks.
• Procedures: drainage of abscess; surgical debridement for necrotising infection; fasciotomy for compartment syndrome; lymphoedema therapy once infection settles.
• Special groups: pregnancy, flucloxacillin or penicillin V; injection drug users, screen for endocarditis and blood borne viruses; breast cancer survivors, early treatment and lymphoedema care; diabetes, tight glycaemic control.
• Red flags: pain out of proportion, bullae, crepitus, rapidly spreading erythema, tense swelling with neurovascular compromise, hypotension, new murmur, fever beyond 48 hours.
• Follow-up: review at 48 to 72 hours; lymphoedema referral; skin care and prophylaxis for recurrent episodes.