Lymph node infection

Lymph node infection also known as lymphadenitis, is the medical term for enlargement in one or more lymph nodes, usually due to infection. Lymph node infection is a complication of certain bacterial infections. Lymph nodes are small, ovoid nodules normally ranging in size from a few millimeters to 2 cm. Lymph nodes are distributed in clusters along the course of lymphatic vessels located throughout the body. The primary function of lymph nodes is to filter out microorganisms and abnormal cells that have collected in lymph fluid ¹. Lymph nodes are filled with white blood cells that help your body fight infections. When lymph nodes become infected, it’s usually because an infection started somewhere else in your body. Rarely, lymph nodes can enlarge due to cancer.

You have about 600 lymph nodes in your body, but normal lymph nodes may only be felt below your jaw, under your arms, and in your groin area.

A normal lymph node is small and firm. When lymph nodes become infected, they usually increase in size, become tender, and may be felt in other areas of your body during a physical exam.

Infections that spread to lymph nodes are usually caused by bacteria, a virus, or a fungus. It is important to learn how the infection spread into your lymph nodes so that the right treatment can be started.

Increased lymph node size may be caused by the following:

Multiplication of cells within the node, including lymphocytes, plasma cells, monocytes, or histiocytes
Infiltration of cells from outside the node, such as malignant cells or neutrophils
Draining of an infection (eg, abscess) into local lymph nodes

Lymph node infection can be one of two types:

Localized lymphadenitis. This is the most common type. Localized lymphadenitis involves one or just a few nodes that are close to the area where the infection started. For example, nodes enlarged because of a tonsil infection may be felt in the neck area.
Generalized lymphadenitis. This type of lymph node infection occurs in two or more lymph node groups and may be caused by an infection that spreads through the bloodstream or another illness that affects the whole body.

Lymphadenitis key points

Lymphadenitis is an infection in one or more lymph nodes.
When lymph nodes become infected, it’s usually because an infection started somewhere else in your body.
Lymphadenitis can cause lymph nodes to become enlarged, red, or tender.
Treatment may include antibiotics, and medications to control pain and fever.
Early treatment of infections can prevent the development of lymphadenitis.

Lymph node infection causes

The lymph system (lymphatics) is a network of lymph nodes, lymph ducts, lymph vessels, and organs that produce and move a fluid called lymph from tissues to the bloodstream.

The lymph glands, or lymph nodes, are small structures that filter the lymph fluid. There are many white blood cells in the lymph nodes to help fight infection. When lymph nodes become infected, it’s usually because an infection started somewhere else in your body.

Lymphadenitis occurs when the lymph glands become enlarged by swelling (inflammation), often in response to bacteria, viruses, or fungi. The swollen glands are usually found near the site of an infection, tumor, or inflammation.

Lymphadenitis may occur after skin infections or other infections caused by bacteria such as streptococcus or staphylococcus. Sometimes, it is caused by rare infections such as tuberculosis or cat scratch disease (bartonella).

Infectious agents causes and lymphadenitis characteristics are as follows ²:

Bartonella henselae (catscratch disease) – Single-node involvement determined by scratch site; discrete, mobile, nontender
Coccidioides immitis (coccidioidomycosis) – Mediastinal
Cytomegalovirus – Generalized
Dental caries/abscess – Submaxillary
Epstein-Barr virus (mononucleosis) – Anterior cervical, mediastinal, bilateral; discrete, firm, nontender
Francisella tularensis (tularemia) – Cervical, mediastinal, or generalized; tender
Histoplasma capsulatum (histoplasmosis) – Mediastinal
Atypical Mycobacterium – Cervical, submandibular, submental (usually unilateral); most commonly in immunocompetent children aged 1-5 years ³
Mycobacterium tuberculosis – Mediastinal, mesenteric, anterior cervical, localized disease (discrete, firm, mobile, tender); generalized hematogenous spread (soft, fluctuant, matted, and adhere to overlying, erythematous skin)
Parvovirus – Posterior auricular, posterior cervical, occipital
Rubella – Posterior auricular, posterior cervical, occipital
Salmonella – Generalized
Seborrheic dermatitis, scalp infections – Occipital, postauricular
Staphylococcus aureus adenitis – Cervical, submandibular; unilateral, firm, tender
Group A streptococcal pharyngitis – Submandibular and anterior cervical; unilateral, firm, tender
Toxoplasma gondii – Generalized, often nontender
Viral pharyngitis – Bilateral postcervical; firm, tender
Yersinia enterocolitica – Cervical or abdominal
Yersinia pestis (plague) – Axillary, inguinal, femoral, cervical; extremely tender with overlying erythema

Immunologic or connective tissue disorders causing lymphadenitis are as follows:

Juvenile rheumatoid arthritis
Graft versus host disease

Primary diseases of lymphoid or reticuloendothelial tissue causing lymphadenitis are as follows:

Acute lymphoblastic leukemia
Lymphosarcoma
Reticulum cell sarcoma
Non-Hodgkin lymphoma
Malignant histocytosis or histocytic lymphoma
Nonendemic Burkitt tumor
Nasopharyngeal rhabdomyosarcoma
Neuroblastoma
Thyroid carcinoma, chronic lymphocytic thyroiditis
Histiocytosis X
Kikuchi disease
Benign sinus histiocytosis
Angioimmunoblastic or immunoblastic lymphadenopathy
Chronic pseudolymphomatous lymphadenopathy (chronic benign lymphadenopathy)

Immunodeficiency syndromes and phagocytic dysfunction causing lymphadenitis are as follows:

Chronic granulomatous disease of childhood
Acquired immunodeficiency syndrome
Hyperimmunoglobulin E (Job) syndrome

Metabolic and storage diseases causing lymphadenitis are as follows:

Gaucher disease
Niemann-Pick disease
Cystinosis

Hematopoietic diseases causing lymphadenitis are as follows:

Sickle cell anemia
Thalassemia
Congenital hemolytic anemia
Autoimmune hemolytic anemia

Miscellaneous disorders causing lymphadenitis are as follows:

Kawasaki disease
PFAPA (periodic fever, aphthous stomatitis, pharyngitis, and adenitis) syndrome
Sarcoidosis
Castleman disease (also known as benign giant lymph node hyperplasia)

Medications causing lymphadenitis are as follows:

Mesantoin – most commonly causes cervical lymphadenitis
Hydantoin – Generalized lymphadenopathy.

Regional lymphadenitis

In a patient with regional lymphadenitis, knowledge of lymphatic drainage patterns and pathologic processes most likely to affect these areas can facilitate diagnostic investigation ⁴.

Cervical lymph nodes

Cervical lymph nodes receive lymphatic drainage from the head, neck, and oropharyngeal cavities.

Infections associated with cervical lymph nodes are as follows ⁵:

Skin and soft tissue infections of the face
Dental abscesses
Otitis externa
Bacterial pharyngitis
Cytomegalovirus
Adenovirus infection
Rubella
Toxoplasmosis

Malignancies associated with cervical lymph nodes are as follows:

Hodgkin lymphoma
Non-Hodgkin lymphomas
Squamous cell carcinomas of nasopharyngeal or laryngeal structures

Axillary lymph nodes

Axillary lymph nodes receive lymphatic drainage from upper extremities and breasts.

Infections associated with axillary lymph nodes are as follows:

Bartonella henselae infection (catscratch disease)
Sporotrichosis
Tularemia
Staphylococcal or streptococcal skin infections

Malignancies associated with axillary lymph nodes are as follows:

Lymphoma
Melanoma
Carcinoma of the breast

Epitrochlear lymph nodes

Epitrochlear lymph nodes receive lymphatic drainage from the hands.

Infections associated with epitrochlear lymph nodes are as follows:

Skin and soft tissue infections from local trauma

Malignancies associated with epitrochlear lymph nodes are as follows:

Lymphoma

Supraclavicular lymph nodes

Supraclavicular lymph nodes receive lymphatic drainage from the chest and mediastinum.

Infections associated with supraclavicular lymph nodes are as follows:

Intrathoracic mycobacterial, fungal infections (not bacterial pneumonias or bronchial infections)

Malignancies associated with supraclavicular lymph nodes are as follows (Note: supraclavicular lymphadenitis is an ominous sign of malignancy):

Intrathoracic and intra-abdominal malignancies (Note: left-sided supraclavicular sentinel node or the Virchow node is highly suggestive of an occult abdominal neoplasm.)
Breast cancer

Other diseases associated with supraclavicular lymph nodes are as follows:

Sarcoidosis

Inguinal lymph nodes

Inguinal lymph nodes receive lymphatic drainage from the lower extremities and skin of the lower abdomen, genitals, and perineum ⁶.

Infections associated with inguinal lymph nodes are as follows:

Cellulitis of the lower extremities
Venereal infections – Syphilis, chancroid, herpes simplex virus infection, lymphogranuloma venereum

Malignancies associated with inguinal lymph nodes are as follows:

Lymphomas
Metastatic melanomas from lower extremity primary site
Squamous cell carcinomas from genital primary site

Note: lymphatic drainage from internal pelvic organs and testes drain via iliac nodes into the para-aortic chain. Therefore, deep pelvic infections or malignancies do not present as inguinal lymphadenitis.

Hilar or mediastinal lymph nodes

Hilar or mediastinal lymph nodes receive lymph drainage from local structures and are usually found on radiologic examination.

Infections associated with hilar or mediastinal lymph nodes are as follows:

Tuberculosis
Fungal infections

Malignancies associated with hilar or mediastinal lymph nodes are as follows:

Bronchogenic carcinoma
Lymphoma
Hodgkin lymphoma

Other diseases associated with hilar or mediastinal lymph nodes are as follows:

Sarcoidosis

Intra-abdominal or retroperitoneal lymph nodes

Intra-abdominal or retroperitoneal lymph nodes receive lymph drainage from local structures, these are typically detected by finding a palpable mass on physical examination or by obstructive/pressure effects on surrounding structures.

Infections associated with intra-abdominal or retroperitoneal lymph nodes are as follows:

Tuberculosis ⁷
Yersinia enterocolitica infection
Deep abscess

Malignancies associated with intra-abdominal or retroperitoneal lymph nodes are as follows:

Hodgkin lymphoma (pelvic and retroperitoneal nodes)
Non-Hodgkin lymphoma (mesenteric nodes)

Generalized lymphadenitis

In a patient with generalized lymphadenitis, the differential includes systemic conditions.

Associated medication toxicities are as follows:

Hydralazine
Allopurinol

Associated infections are as follows:

Epstein-Barr virus infection
Cytomegalovirus infection
Toxoplasmosis
HIV disease
Tuberculosis (advanced)
Histoplasmosis
Coccidioidomycosis
Brucellosis
Bacterial endocarditis
Hepatitis
Syphilis (secondary)

Associated immunologic diseases are as follows:

Sarcoidosis
Rheumatoid arthritis
Lupus

Associated malignancies are as follows:

Acute lymphoblastic leukemia
Chronic lymphocytic leukemia
Lymphomas
Angiofollicular lymph node hyperplasia (Castleman disease)

Lymph node infection symptoms

The symptoms of lymphadenitis may look like other medical conditions or problems. Always see your healthcare provider for a diagnosis.

The main symptom of lymphadenitis is enlarged lymph nodes. A lymph node is considered enlarged if it is about one-half inch wide. Symptoms caused by an infected lymph node or group of nodes may include:

Lymph nodes that increase in size
Lymph nodes that are painful to touch
Lymph nodes that are soft or matted together
Redness or red streaking of the skin over lymph nodes
Lymph nodes that are filled with pus (an abscess)
Fluid that drains from the lymph nodes to the skin
Swollen, tender, or hard lymph nodes
Fever

Lymph nodes may feel rubbery if an abscess (pocket of pus) has formed or they have become inflamed.

Cervical lymphadenitis can lead to neck stiffness and torticollis.

Preauricular adenopathy is associated with several forms of conjunctivitis, including unilocular granulomatous conjunctivitis (catscratch disease, chlamydial conjunctivitis, listeriosis, tularemia, or tuberculosis), pharyngeal conjunctival fever (adenovirus type 3 infection) and keratoconjunctivitis (adenovirus type 8 infection).

Retropharyngeal node inflammation can cause dysphagia or dyspnea.

Mediastinal lymphadenitis may cause cough, dyspnea, stridor, dysphagia, pleural effusion, or venous congestion.

Intra-abdominal (mesenteric and retroperitoneal) adenopathy can manifest as abdominal pain.

Iliac lymph node involvement may cause abdominal pain and limping.

Lymph node infection possible complications

Untreated lymph node infection may lead to:

Abscess formation
Cellulitis (a skin infection)
Fistulas (seen in lymphadenitis that is due to tuberculosis)
Sepsis (bloodstream infection)

Lymph node infection diagnosis

If you have lymphadenitis, the most important parts of your diagnosis are usually your history and the physical exam done by your healthcare provider. You may be asked about your symptoms, such as chills and fever, any recent travel, any breaks in your skin, and recent contact with cats or other animals. Then, during the physical exam, your healthcare provider will look for signs of infection near the enlarged lymph nodes. This includes feeling your lymph nodes and looking for signs of injury or infection around any swollen lymph nodes.

These tests may be needed to help make the diagnosis ⁸:

Blood tests to look for infection.
Blood cultures may reveal spread of infection (often bacteria) to the bloodstream.
A biopsy (taking a sample of tissue) from the lymph node or fluid from inside the lymph node to study under a microscope
Culture of aspirated tissue or biopsy specimen – To determine the causative organism and its sensitivity to antibiotics
Gram stain of aspirated tissue – to evaluate bacterial causes
Monospot or Epstein-Barr virus (EBV) serologies – to confirm the diagnosis of infectious mononucleosis
Bhenselae serologies – to confirm the diagnosis of catscratch disease (if exposed to cats)
Skin testing or purified protein derivative (PPD) – to confirm the diagnosis of tuberculous lymphadenopathy; alternative is interferon-gamma release assays (IGRA) ⁹
Complete blood cell count (CBC count) – elevated white blood cell count may indicate an infectious etiology
Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) – elevated ESR and CRP are nonspecific indicators of inflammation
Liver function tests – may indicate hepatic or systemic involvement; elevated transaminase levels can be seen in infectious mononucleosis

Imaging studies

Ultrasonography may be useful for verifying lymph node involvement and taking accurate measurements of enlarged nodes. A study by Wang et al ¹⁰ indicated that endobronchial ultrasonography can aid in differentiating between nonmalignant intrathoracic lymphadenopathies, including tuberculosis, sarcoidosis, and reactive lymphadenitis. The investigators found that the presence of reactive lymphadenitis is predicted by the existence of central hilar structure and a lack of clustered formation, as well as by vascular pattern (hilar perfusion or avascularity). Best diagnostic accuracies of 77.1%, 89.2%, and 87.1% were found for tuberculous nodes, sarcoid nodes, and reactive lymphadenitis, respectively ¹⁰.

Chest radiography may be helpful in determining pulmonary involvement or spread of lymphadenopathy to the chest.

Lymph node infection treatment

Lymphadenitis may spread within hours. Treatment should begin right away. However, the exact type of treatment depends on what type of infection has spread into your lymph nodes. Once an infection has spread into some lymph nodes, it can spread quickly to others and to other parts of your body, so it’s important to find the cause of the infection and start treatment quickly.

Treatment for lymphadenitis may include:

Antibiotics given by mouth or injection to fight an infection caused by bacteria
Medicine to control pain and fever e.g., analgesics or painkillers
Anti-inflammatory medicines to reduce inflammation and swelling
Cool compresses to reduce inflammation and pain
Surgery may be needed to drain a lymph node that has filled with pus.

Antimicrobial therapy is used when nodes are greater than 2-3 cm, are unilateral, have overlying erythema, and are tender. Antibiotics should target common infectious causes of lymphadenopathy, including Staphylococcus aureus and group A Streptococcus. Owing to the increasing prevalence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA), empiric therapy with clindamycin should be considered ¹¹. Trimethoprim-sulfamethoxazole is often effective for methicillin-resistant Staphylococcus aureus (MRSA) infection, but it is not appropriate for group A Streptococcus infections.

Chemotherapy and radiotherapy are used for treatment of cancers.

Lymph node infection prognosis

Prompt treatment with antibiotics usually leads to a complete recovery. It may take weeks, or even months, for swelling to disappear.

References

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Pasternack MS, Marton NS. Lymphadenitis and Lymphangitis, Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 7th ed. 2010. Chapter 92.
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Friedmann AM. Evaluation and management of lymphadenopathy in children. Pediatr Rev. 2008 Feb. 29(2):53-60.
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Sejben I, Rácz A, Svébis M, Patyi M, Cserni G. Petroleum jelly-induced penile paraffinoma with inguinal lymphadenitis mimicking incarcerated inguinal hernia. Can Urol Assoc J. 2012 Aug. 6(4):E137-9.
Raoot A, Dev G. Assessment of Status of rpoB Gene in FNAC Samples of Tuberculous Lymphadenitis by Real-Time PCR. Tuberc Res Treat. 2012. 2012:834836
Leung AK, Davies HD. Cervical lymphadenitis: etiology, diagnosis, and management. Curr Infect Dis Rep. 2009 May. 11(3):183-9.
Willemse SH, Oomens MAEM, De Lange J, Karssemakers LHE. Diagnosing nontuberculous mycobacterial cervicofacial lymphadenitis in children: A systematic review. Int J Pediatr Otorhinolaryngol. 2018 Sep. 112:48-54.
Wang L, Wu W, Teng J, Zhong R, Han B, Sun J. Sonographic Features of Endobronchial Ultrasound in Differentiation of Benign Lymph Nodes. Ultrasound Med Biol. 2016 Sep 7.
Guss J, Kazahaya K. Antibiotic-resistant Staphylococcus aureus in community-acquired pediatric neck abscesses. Int J Pediatr Otorhinolaryngol. 2007 Jun. 71(6):943-8.

Lymph node infection

Lymph node infection