How can an employer discriminate against someone who they hired for having tattoos?

Before I respond to your inquiry, I must state that we have not spoken, I have not reviewed the relevant documents and facts, and I do not represent you.  Therefore, my discussion below is not a legal opinion but is informational only.  Finally, my discussion applies only to issues to which Pennsylvania or Federal law apply, unless otherwise specified. That being said, unless you have an employment contract or collective bargaining agreement that states otherwise, Pennsylvania follows the rule of "at-will" employment.  This means that your employer can terminate your employment for any reason or no reason at all and/or you can terminate your employment for any reason or no reason at all.  It also means that your employer can change your work schedule and assignments as it sees fit.  As for your question about tattoos, simply having a tattoo does not place you into a protected class as the protected classes are race, color, national origin, religion, sex, disability, age, citizenship, genetic information , educational degree, use of service animal or relation to a disabled person.  Philadelphia also has additional classes.  If you feel you are being discriminated against for the reason of being a member of one of these classes, you should contact an employment attorney to discuss your matter.