ELI5: what is the difference between lupus and fibromyalgia

Lupus and fibromyalgia are both conditions that make you feel unwell, but lupus is like your body's army attacking itself, while fibromyalgia is like your body's pain alarm being stuck on high.

Imagine your body is a castle with a great army to protect it.

• In lupus, the army gets confused and starts attacking the castle itself, causing damage to different parts like the skin, joints, or even important organs like the kidneys. This is an autoimmune disease, meaning "auto" (self) and "immune" (protection) are working against you. Think of it like the soldiers using their swords on the castle walls instead of enemies. You might see this as a rash (like a sunburn), achy joints making it hard to play, or feeling super tired all the time. It’s like the castle is constantly under attack and struggling to function.

• In fibromyalgia, the castle is fine, but the alarm system that warns about pain is broken. It's constantly sending out false alarms, even when there's no real danger. It's like the alarm keeps going off even when there are no bad guys around. People with fibromyalgia feel widespread pain all over their bodies, even when they haven't bumped or hurt themselves. They might also feel very tired and have trouble sleeping. So, while the lupus army is actually damaging the castle, the fibromyalgia alarm is just making you think something is wrong all the time.