What Is the Lupus Flu? Symptoms and Causes

The term “lupus flu” can be a source of confusion. It is not a medical diagnosis but a colloquial name for a collection of symptoms that feel much like the seasonal flu. These symptoms signal an increase in lupus disease activity, known as a flare. Lupus is an autoimmune condition where the immune system attacks its own healthy tissues, causing widespread inflammation that creates these flu-like sensations.

Identifying Lupus Flu Symptoms

One of the most reported symptoms of a lupus flare is fatigue. This is not ordinary tiredness but an exhaustion that can make it difficult to perform daily tasks. This fatigue can appear suddenly and without a clear cause, leaving individuals feeling drained of energy.

Widespread pain in the muscles and joints often accompanies the fatigue. The joints, particularly in the hands, feet, and knees, can become painful, stiff, and swollen, with stiffness being most pronounced in the morning. Unlike some forms of arthritis, this joint inflammation in lupus does not cause permanent joint damage.

A persistent, low-grade fever is another sign of a lupus flare. This fever remains below 100°F (38°C) and can be accompanied by chills. Some individuals also experience night sweats, headaches, and swollen glands, which are direct results of the body’s inflammatory response.

Distinguishing from Influenza and Other Illnesses

Differentiating between a lupus flare and a viral infection like influenza is a challenge. The key distinction is the type and onset of symptoms. Influenza has a sudden onset, is characterized by a high fever above 100.4°F (38°C), and includes significant respiratory issues. A cough, sore throat, and a runny or stuffy nose are primary signs of the flu.

In contrast, “lupus flu” symptoms develop more gradually and can be intermittent. While a fever may be present, it is low-grade. A lupus flare lacks the prominent upper respiratory symptoms that define influenza. The absence of a significant cough or sore throat is a strong indicator that the symptoms are related to lupus activity.

It is also useful to distinguish these symptoms from the common cold. A cold is much milder than the flu, and its symptoms are more concentrated in the head. Symptoms like sneezing, a runny nose, and a scratchy throat are common, while the systemic feelings of a lupus flare, such as deep fatigue and widespread joint pain, are far more intense.

Because people with lupus take immunosuppressant medications, their ability to fight off infections is reduced. This makes them more vulnerable to complications from influenza, such as pneumonia. Therefore, correctly identifying the cause of the symptoms has direct implications for proper medical care.

Underlying Causes and Triggers

The flu-like symptoms of a lupus flare are not caused by a virus or bacterium. Instead, they are the result of the body’s immune system becoming dysregulated. The immune system produces autoantibodies that mistakenly identify the body’s own cells as threats. This triggers widespread inflammation, which produces the feelings of feverishness, aches, and fatigue.

These flares can be set off by a variety of factors. Exposure to ultraviolet (UV) light from the sun or fluorescent lighting is a known trigger. Both physical and emotional stress can also precipitate a flare, as can a lack of adequate sleep.

Infections themselves can sometimes trigger a lupus flare, creating a cycle where a virus might lead to increased autoimmune activity. Certain medications may also trigger lupus activity. Recognizing personal triggers is part of managing the condition, as avoiding them can help reduce the frequency of flares.

Management and Medical Consultation

When symptoms of a suspected lupus flare arise, several at-home strategies can help manage the discomfort. Prioritizing rest allows the body to cope with fatigue and inflammation. Staying hydrated and using warm compresses or baths can help soothe aching muscles. Managing stress through relaxation techniques can also be beneficial.

Before using over-the-counter (OTC) medications, exercise caution. Common pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, may not be suitable for everyone with lupus, particularly those with kidney involvement. Always consult with a doctor before taking any new medication to ensure it is safe for your situation.

You should contact your healthcare provider when you experience symptoms that could be either a flare or an infection. Self-diagnosing is risky because an actual infection requires different treatment and can be more serious for someone with a compromised immune system. A physician can perform tests to determine the cause and adjust your lupus medications or prescribe treatment for an infection.

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