Lymphadenitis is a feature of many bacterial, viral, fungal, and protozoal infections. Focal lymphadenitis is prominent in streptococcal infection, tuberculosis or nontuberculous mycobacterial infection, tularemia, plague, cat-scratch disease, primary syphilis, lymphogranuloma venereum, chancroid, and genital herpes simplex. Multifocal lymphadenitis may occur in patients with the following:
Lymphadenitis typically causes pain, tenderness, and lymph node enlargement. Pain and tenderness typically distinguish lymphadenitis from lymphadenopathy. With some infections, the overlying skin is inflamed, occasionally with cellulitis. Abscesses may form, and penetration to the skin produces draining sinuses. Fever is common.
The underlying disorder is usually suggested by history and examination. If not, aspiration and culture or excisional biopsy (1) is indicated.
1. Olivas-Mazón R, Blázquez-Gamero D, Alberti-Masgrau N, et al: Diagnosis of nontuberculous mycobacterial lymphadenitis: The role of fine-needle aspiration. Eur J Pediatr 2020. doi: 10.1007/s00431-020-03875-2
Treatment of lymphadenitis is directed at the cause and is usually empiric. Options include IV antibiotics, typically directed at Staphylococcus aureus and Streptococcus pyogenes; antifungals; and antiparasitics depending on etiology or clinical suspicion. Many patients with lymphadenitis may respond to outpatient therapy with oral antibiotics. However, many patients also go on to form abscesses, which require surgical drainage; an extensive procedure is done with accompanying IV antibiotics. In children, IV antibiotics are commonly needed. Hot, wet compresses may relieve some pain.
Lymphadenitis usually resolves with timely treatment, although residual, persistent, nontender lymphadenopathy is common.