Thank you for your question. First, to address your first question about disorders that affect the sense of taste - yes, there are several types of conditions that can alter the sense of taste. So I encourage you to speak with your doctor
about your concern. Injuries to the nerves that carry taste to the brain can cause distortion, as can things that affect either the part of the brain where the taste is registered or the mucosa of the mouth where the taste is first encountered. For that matter, even things such as problems with the sense of smell can cause distortions in the sense of taste that can be difficult for some people to properly diagnose. Most of these don't make it so that nothing tastes bad, however, and instead will make many things taste either the same or bad. Pica is generally not thought of as a condition that is due to taste, and is instead thought of as something that is more from some other cause. There are occasions that people will have a deficiency of a certain vitamin or mineral, and will attempt to make up for that by eating many different things that may be able to provide that, whether it does or not. Again, please speak with your doctor about this question.