Dust Mite (House Dust Mites) are so tiny, measuring less than 0.3mm, that their translucent bodies are pretty much invisible to the naked eye. They typically live in dust, feeding on dead skin and mould. Within their typical 100-day lifespan, a female can lay up to 100 eggs in her last 5 weeks. Producing around 2,000 faecal particles in the space of 10 weeks, it's no wonder their faecal matter can cause allergic reactions.