Etiology and Pathology
Acute lymphangitis and lymphadenitis refer to acute inflammation of the lymphatic vessels and lymph nodes caused by bacteria such as Streptococcus pyogenes and Staphylococcus aureus. These pathogens enter the lymphatic system through breaks in the skin or mucosa or from other infectious foci, leading to primarily non-purulent infections. Acute lymphangitis in superficial layers spreads along the lymphatic vessels within the subcutaneous connective tissue, manifesting as erysipelas (reticular lymphangitis) or superficial tubular lymphangitis. Deep lymphangitis involves deeper tissues, presenting without visible changes on the surface. Superficial acute lymphadenitis commonly occurs in regions such as the submandibular area, neck, axilla, inner elbow, inguinal region, or popliteal fossa, with the source of infection often originating from conditions such as pharyngeal inflammation, tinea pedis, skin lesions, or purulent skin and subcutaneous infections, including lymphangitis in the associated drainage area.
Clinical Presentation
Tubular lymphangitis is frequently observed in the extremities. Superficial infections present as red streaks beneath the skin, which are tender to the touch and extend proximally as the condition progresses. Deep lymphangitis in the subcutaneous layers does not exhibit these red streaks but may present with linear tenderness. The severity of the condition depends on the virulence of the bacteria and the extent of the infection, with systemic symptoms resembling those of erysipelas.
In mild cases of acute lymphadenitis, the affected lymph nodes are enlarged and tender, while the overlying skin remains normal. Palpable lymph nodes are typically tender and enlarged, with spontaneous resolution often occurring. In more severe cases, the inflamed lymph nodes may clump together to form masses, with the overlying skin becoming red, warm, and increasingly painful. Severe lymphadenitis may lead to lymph node necrosis, with the development of localized abscesses that exhibit fluctuance. Instances of rupture with purulent discharge, fever, leukocytosis, and signs of systemic inflammatory responses may occur.
Diagnosis and Differential Diagnosis
Deep lymphangitis requires differentiation from acute phlebitis. The latter also presents with palpable, cord-like tenderness beneath the skin, distributed along the course of veins and frequently associated with prolonged peripheral catheterization or infusion of irritant medications.
Prevention and Treatment
Management of acute lymphangitis involves addressing the primary site of infection. Red streaks observed on the skin may be treated with wet compresses containing 50% magnesium sulfate. In cases of rapidly spreading redness in the proximal direction, points along the red streaks may be sterilized and punctured perpendicularly with a thick needle, followed by local wet compresses to facilitate anti-inflammatory treatment.
For acute lymphadenitis that has not yet developed into an abscess, it is important to treat the primary infections, such as boils, carbuncles, or acute cellulitis, which often results in the resolution of lymphadenitis after the primary infection is controlled. If an abscess has formed, in addition to the use of antibacterial medications, incision and drainage are required. Aspiration of the abscess may be performed first, followed by incision and drainage under local anesthesia, ensuring that adjacent nerves and blood vessels are not damaged. A small number of cases of acute lymphadenitis that are not treated promptly or effectively may progress to chronic inflammation, leading to prolonged and refractory symptoms.