Here is what I found out from the IRS website:

Effect of foreign earned income exclusion

You must take all your self-employment income into account in figuring your net earnings from self-employment, even if all, or a portion of, gross income was excluded because of the foreign earned income exclusion.

Example:

You are in business abroad as a consultant and qualify for the foreign earned income exclusion. Your foreign earned income is $95,000, your business deductions total $27,000, and your net profit is $68,000. You must pay self-employment tax on all your net profit, even if you claimed the foreign earned income exclusion.