Swollen Tongue: Causes & Treatment

Can Allergies Cause Swollen Lymph Nodes?

Lymph nodes are small glands located throughout the body that play an important role in the immune system. They contain white blood cells that help fight infection and filter out harmful substances. Swollen lymph nodes are a common indication that the body is responding to an infection, illness, or allergy. But can allergies directly lead to swollen lymph nodes?

The short answer is yes, allergies can sometimes cause lymph node swelling. However, this is not the most common cause of swollen lymph nodes. Infections, certain cancers, and autoimmune disorders more frequently lead to enlarged lymph nodes. Still, allergies should be considered as a potential reason for swollen lymph nodes in some cases.

How Allergies Can Lead to Swollen Lymph Nodes

During an allergic reaction, the immune system responds to a typically harmless substance as if it were harmful. This triggers the release of chemicals like histamine that lead to common allergy symptoms such as sneezing, coughing, or a runny nose. Lymph nodes may become swollen as they work to filter out these allergens and respond to the chemicals released during an allergic response.

Those with allergies such as hay fever may notice swollen lymph nodes in the neck when their allergies are flaring up. This is because the lymph nodes in the neck filter fluids from the head and neck areas that commonly come in contact with airborne allergens. The swelling signifies that the lymph nodes are working to remove the allergens from the body.

Food allergies can also sometimes lead to swollen lymph nodes, particularly in the neck, groin, and armpits. This occurs as the lymph nodes filter out the food proteins that trigger an allergic reaction. The swelling may coincide with other food allergy symptoms such as tingling in the mouth, abdominal pain, nausea, vomiting, diarrhea, or hives.

Additionally, certain allergic skin conditions like eczema or contact dermatitis can cause lymph nodes near affected areas to become swollen as they drain and filter fluid from the inflamed skin. For example, hand eczema may lead to swollen lymph nodes in the elbow and arm.

Other Causes of Swollen Lymph Nodes

While allergies can cause swollen lymph nodes, it is not the most likely cause. Swollen lymph nodes are far more often due to infections, particularly viral upper respiratory infections like the common cold, influenza, mononucleosis, or COVID-19. Bacterial infections, including streptococcal pharyngitis (strep throat) and cat scratch disease may also lead to enlarged lymph nodes as they help fight off infection.

Cancers that arise in lymph node-rich areas may also spread to nearby lymph nodes and cause swelling. Lymphomas, which are cancers that originate from lymphocytes, often lead to lymph node enlargement. Leukemias, breast cancer, melanoma, and cancers in the head and neck area commonly spread to lymph nodes as well.

Autoimmune and immune disorders like rheumatoid arthritis, lupus, and HIV/AIDS can cause systemic lymphadenopathy affecting lymph nodes throughout the body. This occurs because the immune system is overstimulated and the lymph nodes become hyperactive. Certain medications used to treat autoimmune disorders may also lead to swollen lymph nodes in some cases.

Dental infections, piercings, tattoos, and injuries or trauma to lymph node areas can cause localized lymph node swelling as they respond to inflammation. Lipomas or cysts in the lymph node regions may also put pressure on lymph nodes and lead to enlargement.

Distinguishing Allergy-Related Swollen Lymph Nodes

Because allergies are not the most common cause of swollen lymph nodes, additional symptoms and timing often help distinguish allergy-related lymphadenopathy. Swollen lymph nodes that appear simultaneously with other symptoms of an allergic reaction make an allergy a more likely culprit.

Allergy-related swollen lymph nodes also tend to appear rapidly but shrink quickly as well, often disappearing within days or weeks as the allergic response subsides. In contrast, lymph node swelling from infections, cancers, and immune disorders is more persistent and progresses slowly without treatment.

The location of swollen lymph nodes also provides insight into the cause. Widespread lymph node enlargement affecting lymph nodes throughout the body is unlikely to be from an allergy. Allergy-related swelling most often appears in lymph nodes close to the site of allergen exposure, such as those in the neck and head after exposure to airborne allergens.

A doctor can help distinguish allergy-related swollen lymph nodes from enlargement due to other causes by considering the persons medical history and performing an exam. They may recommend imaging or laboratory tests if cancer or infection is suspected as the cause.

Treating Swollen Lymph Nodes from Allergies

The main way to treat swollen lymph nodes caused by allergies is to control the allergic response with medications such as:

• Antihistamines like diphenhydramine (Benadryl) or loratadine (Claritin) to reduce symptoms
• Nasal corticosteroid sprays to decrease inflammation
• Immunotherapy or "allergy shots" to gradually make the body less sensitive to allergens

Avoiding exposure to allergens whenever possible also helps reduce flare ups and subsequent lymph node swelling. An allergy specialist can help identify specific allergy triggers through skin or blood tests.

For food allergies, carefully checking ingredient labels and avoiding consumption of food allergens is key. Washing hands and showering after exposure to allergens can rinse pollen and other triggers from the skin and hair to prevent further exposure.

Swollen lymph nodes from allergies often resolve on their own once the allergic response calms down. But antihistamines and corticosteroids can help reduce swelling and other allergy symptoms. See a doctor promptly if the swollen lymph nodes do not diminish after the allergy flare up resolves.

When to See a Doctor

In most cases, mild swelling of one or several lymph nodes resolves on its own. However, see a doctor if any of the following occur:

• Lymph nodes are very large or painful
• Swelling lasts longer than 2-4 weeks
• You have fever, night sweats, unexplained weight loss
• Swollen lymph nodes develop without any other illness or allergy symptoms

These signs may indicate an infection, autoimmune disorder, or possibly cancer instead of just allergies. Your doctor can examine the cause and order blood work or imaging tests if needed to reach an accurate diagnosis.

The Bottom Line

Allergies can sometimes cause swollen lymph nodes, but many other conditions like infections and cancers more commonly lead to enlarged lymph nodes. The location and timing of swelling provides clues about whether allergies are the likely cause. See a doctor for any unexplained lymph node swelling lasting longer than a few weeks to identify the underlying reason.

Controlling allergy symptoms and avoiding triggers are the main ways to treat allergy-related swollen lymph nodes. Antihistamines, nasal sprays, and immunotherapy can help suppress the allergic response. Swollen lymph nodes due to allergies often diminish once the flare up resolves. But prompt medical attention is necessary for persistent enlarged lymph nodes to diagnose and manage any serious underlying problem.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.