I'm not a medical professional, but I can offer some general suggestions. It's important for the person dealing with gout to consult with a healthcare professional for personalized advice. That being said, here are some alternative exercises that may be less likely to irritate the big toe affected by gout:

Swimming: Water exercises are generally gentle on the joints. Swimming or water aerobics can provide a good workout without putting excessive stress on the big toe.

Cycling: Riding a stationary bike or cycling outdoors can be a low-impact alternative to lunges. Ensure proper shoe support and make adjustments to the pedal and seat height for comfort.

Elliptical Trainer: Using an elliptical machine can be a good option as it offers a low-impact workout. It minimizes stress on the joints compared to activities like running or jumping.

Seated Leg Exercises: You can perform seated leg lifts or extensions to work on your leg muscles without putting pressure on the big toe. These can be done using resistance bands or machines at the gym.

Partial Squats: Instead of full lunges, you might try partial squats. These involve bending your knees slightly without going into a full lunge position. Be sure to maintain proper form and stop if you experience any discomfort.

Remember, it's crucial to listen to your body and avoid any exercises that cause pain or discomfort. If the pain persists or worsens, it's important to consult with a healthcare professional for guidance tailored to your specific situation.