Causes

The possible causes of lymph node swelling can be roughly divided into two categories: Infections and malignant processes. If an infection is the cause of the swelling, we are talking about lymphadenitis in the narrower sense, i.e. inflammation of the lymph nodes, as discussed in this article. Numerous bacterial and viral pathogens can enter the body and be filtered and “discovered” in the lymph nodes, resulting in increased activity of the lymph nodes and thus their swelling.

Here are a few examples in more detail: The cat scratch disease is a disease whose bacterial pathogen – Bartonella henselae – is transmitted by cats. It occurs more frequently in children than in adults and is characterized by swelling of the lymph nodes, especially in the neck and/or armpits (swelling of the lymph nodes in the armpits). Other symptoms such as fever, fatigue, headache, chills and sore throat may also occur.

In addition, at the beginning, shortly after infection with the pathogen, a small brownish skin lesion often appears which disappears within a few days and often goes unnoticed. The disease often progresses unnoticed, but it can also lead to complicated processes that mainly affect the central nervous system (for example encephalitis, paralysis). But also the heart (endocarditis), the lungs (pneumonia), the eye (retinitis) or the liver can be affected.

The blood may show a breakdown of red blood cells (haemolysis) and a lack of blood platelets (thrombocytopenia). To secure the diagnosis, antibody detection against the bacterium in the blood and the detection of the bacterium in a molecular biological examination, the PCR, must be carried out. Often the disease heals without specific therapeutic measures, sometimes antibiotics are used.

Another bacterial infectious disease that can manifest itself by swelling of the lymph nodes is Lymphgranuloma venerum, also known as Lymphgranuloma inguinale. The disease is caused by the bacterium Chlamydia trachomatis and is one of the sexually transmitted diseases (STD). It is characterized by swelling of the lymph nodes in the groin area near the intimate region.

The swelling is clearly painful, sometimes the skin in the area of the swollen lymph nodes has a reddish-bluish color. Treatment with certain antibiotics (macrolides or tetracyclines) should always be carried out as otherwise the disease may become chronic. The sexual partner should always be treated with antibiotics as otherwise the disease can be transmitted from one to the other.

Also the illness of the human being called yersiniosis can lead to swelling of the lymph nodes. Children and adolescents are particularly affected. Lymph node swelling typically occurs in the area of the abdomen (mesenteric lymph nodes), often symptoms similar to appendicitis (pseudoappendicitis) occur, this can lead to misdiagnosis.

A chronic inflammation of the lymph nodes can be caused by lymph node tuberculosis. Viral pathogens can also be filtered out by the lymph nodes and thus cause their swelling. For example, the Epstein-Barr virus (EBV) which can lead to the clinical picture of mononucleosis, also known as Pfeiffer’s glandular fever (colloquially known as kissing disease).

Almost 100% of Europeans are infected, but only a few show symptoms. In adults, the disease is a flu-like condition, while in adolescents it can lead to swelling of the lymph nodes, sore throat, tonsillitis, fever and swelling of the spleen (splenomegaly). The transmission of the pathogen is mainly via saliva, hence the name kissing disease.

The diagnosis is made by the detection of antibodies against the viral pathogen, often the number of white blood cells (leukocytes) is also increased. There is no specific therapy, possibly antipyretic drugs are prescribed. Infection with the measles virus and the rubella virus can also lead to swelling of the lymph nodes.

Rubella infection typically affects the lymph nodes behind the ears and at the back of the head, while measles infection can cause swelling of numerous lymph nodes in various parts of the body (generalized lymphadenopathy).It should be briefly mentioned here that another important cause of lymph node swelling – besides inflammation caused by infection with pathogens – can be the presence of a malignant process, i.e. a tumor disease. In this case, we are not talking about lymphadenitis but lymphadenopathy (i.e. swelling of the lymph nodes without their inflammation), but these two terms are often used synonymously. Among the tumor diseases that are typically associated with a swelling of the lymph nodes are Hodgkin’s lymphoma and the group of non-Hodgkin’s lymphomas (NHL), which also includes chronic lymphocytic leukemia (CLL).