Is there a relation between social anxiety and low self esteem?

Yes: Social anxiety limits interaction with others. Avoiding social activities due to anxiety often causes isolation and lowers self-esteem. For a good overview, see: http://www.nhs.uk/conditions/social-anxiety/Pages/Social-anxiety.aspx I hope this helps. Best wishes.

Social anxiety: Often those with social anxiety have low self-esteem. One doesn't necessarily cause the other, but I would say, rather then the two phenomena co-occur.

Anxiety self esteem: Social anxiety causes one to isolate form the world. It may stem from low self esteem and having negative past experiences of criticism, harm and fear of repeated uncomfortable moments. Isolation translates into lack of openness and self confidence among peers and others in general. Self acceptance and self love are lacking and the ability to receive love suffers. This lowers self esteem.