Lupus is a chronic (long-lasting) disease where the body’s immune system, which normally defends against harmful things like viruses and bacteria, becomes overactive and mistakenly attacks its own healthy tissues and organs. Instead of just fighting off infections, the immune system starts attacking the body's own cells, causing inflammation and damage in various parts of the body.

There are different types of lupus, but the most common one is called systemic lupus erythematosus (SLE). This type can affect many parts of the body, including the skin, joints, kidneys, heart, lungs, and brain. Some people only experience mild symptoms, while others may face more serious complications.

Symptoms of lupus vary widely and can change over time. Common symptoms include:

• Fatigue: Feeling very tired, even after rest.
• Joint pain and swelling: Pain or swelling in the joints, especially in the hands and knees.
• Rashes: One of the most well-known signs of lupus is a butterfly-shaped rash that appears across the cheeks and nose.
• Fever: A low-grade fever that comes and goes.
• Hair loss: Thinning or shedding of hair.
• Sun sensitivity: Skin rashes may worsen in sunlight.

Lupus can be tricky to diagnose because its symptoms often resemble those of other conditions, and it affects people differently. There is no single test for lupus, so doctors usually consider a person's symptoms, medical history, and lab tests to make a diagnosis.

The exact cause of lupus is not completely understood, but it is thought to involve a combination of genetic factors (something you're born with) and environmental factors (things like infections, stress, or even sunlight) that trigger the immune system to act wrongly.

While there is no cure for lupus, it can be managed with the right treatment. Medications like anti-inflammatory drugs, immune system suppressors, and steroids can help control symptoms and prevent flare-ups. With proper treatment and regular medical care, people with lupus can lead normal lives. However, lupus can sometimes cause serious health problems, especially if organs like the kidneys are affected, so it’s important for people with lupus to stay in close touch with their doctors.

In short, lupus is a disease where the immune system attacks the body by mistake, and while it can be challenging to live with, there are treatments available to manage the symptoms and help people feel better.