Kathryn deBros, Special Educator
Hello! I wrote an article about dyscalculia a while back that you may find helpful (here) but the short version is that children may have dyscalculia when numbers just don't seem to make sense to them - maybe they can repeat the counting sequence, but don't know how to apply it, i.e. repeating all the numbers to ten no matter how many objects they are trying to count in front of them. Another sign is that kids have a hard time recognizing and making patterns, or having trouble recognizing that one group of objects could be more or less than another.
Teachers have a responsibility to identify special needs in children, and most schools have teams of support that teachers will go to when a child's skill is lagging, who can decide when to discuss a special education evaluation. Dyscalculia isn't like having a sickness, where you can diagnose it precisely, but if a student presents a pattern of struggling with math skills and number sense (and either falls in the bottom 15% of the class or doesn't improve with appropriate educational interventions) then they may qualify as a "student with a learning disability in math," otherwise known as dyscalculia.
If you have a concern, I would bring it to your child's teacher and see what he/she thinks. There's a lot of variability in really young children, so it might be that your child needs more time or more attention, but the teacher would have a good perspective on next steps.
Good luck! Kathryn