Can Hydroxychloroquine Cause Swollen Lymph Nodes? Understanding This Rare Side Effect

October 13, 2025 •

4 min read

While uncommon, cases of swollen lymph nodes have been reported in patients taking hydroxychloroquine, primarily as a component of a rare but serious adverse drug reaction called Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). Patients on this medication, often for autoimmune conditions, must understand this potential side effect.

Quick Summary

Swollen lymph nodes are a possible, though rare, side effect of hydroxychloroquine, typically occurring as part of a severe systemic hypersensitivity reaction called DRESS syndrome. Differentiation from underlying disease is crucial.

Key Points

Rare but Serious Risk: Swollen lymph nodes (lymphadenopathy) can be a rare but serious side effect of hydroxychloroquine, primarily associated with a condition called DRESS syndrome.
DRESS Syndrome is a Severe Allergic Reaction: DRESS syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms) involves a serious immune response with symptoms like fever, widespread rash, facial swelling, and internal organ damage.
Delayed Onset is Key: DRESS syndrome symptoms typically appear weeks to months after starting hydroxychloroquine, not immediately.
Differentiate from Underlying Disease: Patients taking hydroxychloroquine for autoimmune diseases like lupus or RA must distinguish between a DRESS reaction and a flare-up of their condition, as autoimmune diseases can also cause swollen lymph nodes.
Immediate Medical Attention Required: If you experience swollen lymph nodes along with fever, rash, or facial swelling while on hydroxychloroquine, contact your healthcare provider immediately.
Prompt Treatment is Crucial for Recovery: The primary treatment for DRESS is stopping the causative drug, and prognosis is good with early intervention, but long-term monitoring may be needed.

Hydroxychloroquine is a medication used to treat autoimmune diseases such as rheumatoid arthritis and lupus, as well as for the prevention and treatment of malaria. While generally considered safe for most users, it can cause a range of side effects, most commonly mild gastrointestinal issues. A less frequent but more severe adverse reaction involves the immune system, and in rare cases, can lead to swollen lymph nodes, a condition known as lymphadenopathy. This article explores the link between hydroxychloroquine and lymphadenopathy, focusing on the specific and serious condition where it most commonly occurs.

The Link Between Hydroxychloroquine and Lymphadenopathy

Lymphadenopathy refers to the swelling or enlargement of one or more lymph nodes, which are small, bean-shaped structures that are part of the body's immune system. Swollen lymph nodes are a sign that the immune system is actively fighting an infection or responding to an inflammatory process. While many conditions, from common colds to more serious infections, can cause lymph nodes to swell, certain medications can also trigger this response.

One study indicated that hydroxychloroquine has a high affinity for lymphoid tissues, where it can accumulate. This distribution of the drug in the lymphatic system is a key factor in its therapeutic action but can also contribute to adverse immune reactions. However, it's not the normal drug accumulation that causes swelling, but rather a severe and abnormal hypersensitivity response.

DRESS Syndrome: A Severe Cause of Swollen Lymph Nodes

The most prominent and concerning cause of hydroxychloroquine-induced lymphadenopathy is Drug Reaction with Eosinophilia and Systemic Symptoms, or DRESS syndrome. This is a rare, but potentially life-threatening, severe allergic reaction that can affect multiple organs.

Symptoms of DRESS Syndrome

In addition to swollen lymph nodes, DRESS syndrome is characterized by a constellation of other symptoms that typically appear two to eight weeks after starting a new medication. It is crucial to recognize these signs immediately and seek medical attention.

Fever: Often a high and persistent fever.
Rash: A widespread, maculopapular rash that can be red, purple, or blistered.
Facial Edema: Swelling of the face.
Eosinophilia: An abnormally high number of a type of white blood cell called eosinophils.
Systemic Involvement: Inflammation and potential damage to internal organs, most commonly the liver, kidneys, or lungs.

While hydroxychloroquine is a known trigger, DRESS syndrome is also associated with other drugs, including certain anticonvulsants and antibiotics. Prompt discontinuation of the offending medication is the primary treatment.

Distinguishing Drug-Related Lymphadenopathy from Underlying Disease

For patients taking hydroxychloroquine for an autoimmune condition like lupus or rheumatoid arthritis, the distinction between a drug-induced reaction and a disease flare-up is critical. Autoimmune diseases themselves can cause lymphadenopathy. Below is a table comparing the different presentations.


Feature	DRESS Syndrome (Drug-Induced)	Autoimmune Disease Flare
Onset	Typically delayed, 2–8 weeks after starting the drug.	Variable; can coincide with increased disease activity.
Associated Symptoms	Often includes high fever, widespread rash, facial swelling, and organ dysfunction.	Symptoms typically consistent with the underlying condition (e.g., joint pain in RA, fatigue, butterfly rash in lupus).
Fever	High and persistent fever is common.	Can occur, but may be lower-grade and often a sign of a general flare.
Blood Markers	Elevated eosinophils are a hallmark.	Reflective of general inflammation, may not show marked eosinophilia.
Rash	Often morbilliform, widespread, and potentially severe.	Characteristic skin manifestations of the specific autoimmune disease (e.g., lupus rash).
Prognosis	Good with prompt drug discontinuation and treatment; can be fatal if missed.	Varies with disease severity and treatment response.

What to Do If You Notice Swollen Lymph Nodes

If you are taking hydroxychloroquine and notice swollen lymph nodes, it is essential to act quickly. If you have any accompanying symptoms of DRESS syndrome—such as fever, rash, or facial swelling—you should contact your healthcare provider immediately. Do not stop taking your medication on your own without a doctor's guidance, unless instructed to do so in an emergency, as sudden cessation can also have risks. Your doctor can perform the necessary tests to determine the cause of the lymphadenopathy and decide on the appropriate course of action, which may include stopping the drug and starting a treatment like corticosteroids.

Long-Term Effects and Prognosis

The prognosis for DRESS syndrome is generally favorable with rapid identification and treatment. The lymphadenopathy and other systemic symptoms typically resolve once the causative medication is stopped. However, there is a risk of lasting organ damage if the condition is not addressed in a timely manner. The experience of DRESS can also cause significant psychological distress, and patients may require ongoing monitoring to ensure full recovery. One must also consider the potential for reactivation of certain viruses (e.g., HHV-6), which has been linked to DRESS syndrome and could complicate the clinical picture.

Conclusion

In conclusion, while hydroxychloroquine can cause swollen lymph nodes, it is typically a sign of a rare but serious hypersensitivity reaction known as DRESS syndrome. This condition requires immediate medical attention and is distinguished by a collection of symptoms including fever, rash, and organ inflammation. Patients on hydroxychloroquine should be aware of these potential adverse effects, but also be mindful that their underlying autoimmune condition can also cause lymphadenopathy. Close communication with a healthcare provider is paramount to ensure proper diagnosis and management, leading to the best possible outcome. For more detailed information on DRESS syndrome, please consult reliable medical resources or discuss with a qualified healthcare professional. National Institutes of Health provides additional insights into drug-induced hypersensitivity syndromes.

Frequently Asked Questions

It is very rare for hydroxychloroquine to cause swollen lymph nodes. When it does happen, it is almost always as part of a severe hypersensitivity reaction known as DRESS syndrome, which is itself uncommon.

Besides swollen lymph nodes, DRESS syndrome typically includes a high fever, a widespread skin rash, facial swelling (edema), an abnormal increase in a type of white blood cell called eosinophils, and signs of internal organ involvement.

DRESS syndrome is known for its delayed onset, with symptoms usually appearing two to eight weeks after starting hydroxychloroquine or another causative drug.

Drug-induced lymphadenopathy from DRESS is part of a systemic reaction with a characteristic symptom cluster (high fever, rash, facial swelling) and delayed onset. Lymphadenopathy from an autoimmune flare-up is generally tied to a general increase in disease activity and may have a less distinct fever or rash pattern.

No, you should not stop taking hydroxychloroquine without consulting your doctor. If you find a swollen lymph node, especially with other symptoms like fever or rash, contact your healthcare provider immediately to determine the cause.

If DRESS syndrome is diagnosed, the hydroxychloroquine will be discontinued immediately. Treatment often includes corticosteroids to manage the systemic inflammation, and supportive care is provided for any affected organs.

Yes. Swollen lymph nodes are a very common symptom of many infections, from viral colds to more serious bacterial illnesses. Your doctor will need to perform tests to determine the exact cause of the swelling.