Begin with rice cereal or any simple fruit or vegetable easily pureed. Introduce small portions at a time, gradually increasing over several weeks. Start one ingredient at a time to get baby accustomed to tastes and textures. Eventually you will work your baby up to three solid meals per day. What may appear to be an allergic reaction to you may turn out to be something completely different.
Patience is key when it comes to weaning.
If ever it feels like a struggle, stop trying to introduce solids until a later date. It is common for your baby to like something one day and refuse it the next. Do not get discouraged, this is a natural part of the learning to eat process. Allowing your baby to play with the food will help them understand food texture and hand to mouth coordination. If all else fails, it could just not be the right time to offer solids to your baby.