Sayyidah Aishah (may Allah be pleased with her) was asked: May the one in ihram scratch his body? She said: Yes, let him scratch it well. And she said: If my hands were tied and I had nothing to scratch with except my feet, I would scratch with my feet.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9141