Why are the gout flare-ups in my toe worse in summer?

I've had gout for years and despite taking 600mg allopurinol, I still get really painful flareups in my big toe, which have been particularly bad this summer. Should I increase the dose of allopurinol or are there any better alternatives?

- Dr Rosemary Leonard

Gout is caused by raised levels of uric acid in the blood. Uric acid is normally harmless, and any excess is passed out in the urine. However, in people with gout, the levels rise and tiny crystals of it may form and collect in joints, leading to inflammation, swelling and often severe pain - a gout attack.