Our bodies have many vascular systems to circulate materials from or to different cells and tissues. The most popular is the systemic circulatory vascular system, which connects body cells to the heart and lungs via arteries and veins, but we have another important system with a similar function, the lymphatic system. The lymphatic system has two main functions, one is related to the gastrointestinal tract or gut. Here, it is useful to transport absorbed fat. But the more important function is acting as a “filter” of foreign organisms or material that either enters through our skin or natural orifices, and even for cancer cells if they travel from the site of origin. Our lymphatic system is formed by channels called lymph vessels and filters called lymph nodes.
This overall view can help us understand how a lymph node can be swollen. In a way, a swollen lymph node is like a clogged drain, and doctors think of it as such. The main point to be considered regarding any lymph node enlargement is the number of lymph nodes involved. If two non-neighboring lymph nodes are affected, it is called a generalized lymphadenopathy and has a separate set of diagnoses than isolated enlarged lymph nodes. The other point to be considered is where the clogging started from. We call this a “focus”. Other causes of lymph node enlargement may be related to the lymph nodes themselves, especially in metabolic diseases and autoimmune disease. After all, lymph nodes are an essential part of the body’s immune system.
What is special about the occipital lymph nodes
The occipital lymph nodes are located at the back of your head, at the upper part of your nape. When enlarged, they can be located anywhere form the middle of your hairline at the back to behind your ears. Anatomically speaking, the occipital lymph nodes drain your scalp and are more likely to enlarge due to a problem in the scalp. They may not be easily noticed when they become enlarged if you have long hair or if they are not painful.
Occipital lymph nodes are a part of the transverse group of cervical lymph nodes. They represent a stage before eventually draining, with the rest of the neck’s lymph nodes, into the deep cervical lymph nodes. Therefore, if they are swollen, your doctor will pay a special care to examine your neck lymph nodes and your scalp to understand the extent of the problem.
What can cause enlarged occipital lymph nodes
The medical classification of lymph node conditions is divided according to the cause. They can be inflammatory or cancerous (neoplastic). The inflammatory type is then subdivided into that of a specific infection like tuberculosis or leprosy or the non-specific type -the most common cause of lymph node enlargement-, which results from a bacterial or viral infection that drained into the neighboring lymph nodes. The cancerous or neoplastic type is further subdivided into primary as leukemia or lymphoma or secondary when cancer affecting the area drained in this group of lymph nodes. The former scheme is studied in detail by doctors, but is less relevant for normal people because we can´t stress enough how common unspecific infections are and how uncommon diseases like leprosy are. Therefore, we will arrange the causes according to their likelihood.
Infection
Generally speaking, any infection that involves the “territory” drained by the lymph nodes can cause their enlargement. In the case of occipital lymph nodes, this includes any bacterial infection of the scalp, for example, by bacteria found on your fingernails when you vigorously scratch your scalp and break the skin. They are still non-harmful bacteria if the skin is intact, but a broken skin will become a breach of the defenses of your body.
Although bacterial infections are the most common in the scalp, other infections can be present, such as viral infections, but these are much more likely to involve all lymph nodes of the head and neck rather than just the occipital lymph nodes because they are introduced mostly through the nose and mouth. Some parasitic infections as head lice can or scabies cause swollen lymph nodes, especially since they are itchy so they can cause what we call a “secondary bacterial infection” through lesions produced when the person scratches their head. Some fungal infections such as tinea capitis (ring worm) or favus (yellow Sulphur cup) can cause a mixed infection of fungus and bacteria, enlarging the lymph nodes.
Tuberculosis is nowadays quite rare in developed countries, but in those who have an epidemic of malnutrition, especially in Africa, it remains a serious problem. Tuberculosis can enlarge the lymph nodes to the extent of forming an abscess. The worst part is that this abscess can never be drained as an ordinary one, and any attempt of drainage will leave a lifelong unhealed ulcer or an unsightly scar.
The main challenge for the diagnosis of infectious enlarged lymph nodes is that doctors have to locate the origin of infection. Lymph node size is not the main problem and it will most likely subside following proper treatment of the origin. Some infections are hidden and need proper examination and investigations before prescribing an appropriate treatment.
Autoimmune diseases
Autoimmune diseases were poorly understood in the past leading to a spike of new diagnoses and treatments. One of the main manifestations of many autoimmune diseases is enlarged lymph nodes because of the rise of chemical mediators released to the bloodstream. They push the entire immune system to increase the number of cells. In turn, they also release new mediators in a vicious cycle that destroys many organ systems. In this scenario, enlarged lymph nodes are basically formed by those immune cells. All autoimmune diseases have the potential of causing enlarged lymph nodes. The most common are systemic lupus, rheumatoid arthritis and sarcoidosis.
Autoimmune diseases affect the whole body, and therefore many lymph nodes will be enlarged, including the occipital lymph nodes. Your doctor will perform a general examination and will order a battery of investigations which may include taking a biopsy to confirm the diagnosis. Autoimmune diseases are treated in a very different way than any other condition affecting the lymph nodes, and a mistreatment can lead to severe conditions.
Cancer
Cancer is commonly associated with the term “tumor”. Although this association is not scientifically accurate, it does picture one of the forms of cancer, similar to a swelling. Swollen organs have a chance of becoming cancerous. After all, cancer is nothing but an unchecked division of cells. Regarding lymph nodes, they can be affected by cancer in 2 ways. Firstly, if cancer originated within their tissues or within blood cells, and secondly, if cancer originated in the territory they drain, and cancer cells were filtered through lymph channels and became dislodged within the lymph nodes and continued dividing, this condition is called a “metastatic cancer”. Although both conditions are broadly known as cancer, their management and outcome vary greatly.
An important aspect to consider is how to differentiate between a cancerous and an inflammatory lymph node. The common saying is that “if it hurts, it’s good”. While this is largely true, it can’t be used as a general rule. Some cancerous lymph nodes can be infected or may even be painful without infection, especially in late stages of the disease. The other more important aspect is the clinical examination. Cancerous lymph nodes feel harder and are less mobile than inflammatory lymph nodes. Again, there are no absolutes, and in some cases of Hodgkin’s lymphoma, lymph nodes are rubbery. If the diagnosis proves challenging via history and clinical examination, your doctor may order a biopsy or an ultrasound, ideally both.
Generally speaking, if a metastatic cancer occurs, it usually affects a limited number of lymph nodes and most or all of them are within the same line of drainage, whereas lymphoma “cancer of the lymph nodes” and leukemia “blood cancer” usually involve many non-neighboring lymph nodes. A very thorough examination of the area drained by the affected group of lymph nodes is required. In case of occipital lymph nodes, the most likely culprit in cancer is a squamous cell carcinoma of the scalp. It looks like an ulcer or a non-healing wound. Another cancer that may spread to the lymph nodes from the scalp is melanoma, a cancer originating from melanocytes, the cells responsible for the color of your skin. The presence of lymph node involvement in skin cancer changes its management and its classification. We call it a “stage”. When cancer involves a greater area, a neighboring organ or even spreads to other parts whether through lymphatics or blood, we advance its stage and change its treatment accordingly.
Metabolic diseases
Metabolic diseases are quite rare yet important causes of lymph node enlargement. Like autoimmune diseases, they involve the whole body and affected lymph nodes are multiple. They originate from a genetic anomaly that causes the body to accumulate certain food byproducts in an abnormal form. They include 2 main categories, lipid storage diseases and glycogen storage diseases. They shouldn’t be confused with amyloidosis which, although causes an enlargement of lymph nodes, it is not a metabolic disease but a complex process of accumulation of an abnormal protein. It may have a genetic component or may simply result from old age “senile amyloidosis”.
It is easy to be afraid of a swelling that appeared out of nowhere in your neck, but don’t rush to draw a conclusion or resort to self-medication. Consulting your doctor is always a good option, and if he/she decides that it is worth investigating further, they will order a battery of exams or prescribe treatment that will best manage your condition.