Lymphangitis

Lymphangitis is inflammation of the lymphatic vessels draining an infected site, producing red streaks along the limb toward regional nodes. It is usually acute and bacterial (group A streptococcus, Staphylococcus aureus), but can be nodular (fungal, mycobacterial) or filarial.

• Common portals: wounds, cellulitis, tinea, paronychia, insect bites, injection sites, ulcers.
• Risk factors: diabetes, immunosuppression, lymphoedema, previous lymphangitis.

Painful red linear streaks extending from a wound toward the axilla or groin, with tender enlarged regional lymph nodes, fever, chills and malaise.

• Nodular (sporotrichoid) lymphangitis: a chain of subcutaneous nodules and ulcers along the lymphatic.
• Differential diagnosis: superficial thrombophlebitis, cellulitis, contact dermatitis, sporotrichosis, Nocardia, Mycobacterium marinum, leishmaniasis, tularaemia, filarial lymphangitis, venous thrombosis, insect envenomation.
• Complications: bacteraemia and sepsis, abscess, lymphadenitis, chronic lymphoedema, recurrence, necrotising infection.

Clinical.

• Full blood count, CRP, blood cultures if febrile; swab or aspirate the portal of entry.
• Tissue culture and biopsy for nodular lymphangitis (fungal, mycobacterial stains); ultrasound for abscess or venous thrombosis.
• Glucose, HIV test.

Antibiotics for the likely organism, with source treatment.

• Supportive: rest and elevation of the limb, warm compress, analgesia (paracetamol 1 g), clean the wound, tetanus toxoid if due.
• Pharmacological: flucloxacillin 500 mg to 1 g four times daily for 7 to 10 days (children 12.5 to 25 mg/kg four times daily), or phenoxymethylpenicillin 500 mg four times daily; penicillin allergy: clindamycin 300 to 450 mg three times daily. Severe: benzylpenicillin 1.2 to 2.4 g IV every 6 hours with flucloxacillin 1 to 2 g IV every 6 hours; MRSA risk: vancomycin 15 to 20 mg/kg IV every 12 hours. Nodular lymphangitis from sporotrichosis: itraconazole 200 mg daily for 3 to 6 months; Mycobacterium marinum: doxycycline 100 mg twice daily with clarithromycin 500 mg twice daily for 3 to 6 months; Nocardia: cotrimoxazole 960 mg twice daily for 3 to 6 months.
• Procedures: drainage of abscess; excision of the primary focus.
• Special groups: pregnancy, flucloxacillin or penicillin V; diabetes, admit when moderate; HIV, culture for fungal and mycobacterial causes; lymphoedema, long term prophylaxis.
• Red flags: rapidly extending streaks, fever with rigors, hypotension, gas or necrosis, no improvement at 48 hours.
• Follow-up: review at 48 hours; treat tinea and wounds; prophylaxis with phenoxymethylpenicillin 250 to 500 mg twice daily if recurrent.