liver function tests need to be done to confirm for liver
dysfunction like liver
function tests, serum proteins, serum albumin and globulin, alanine transaminase, prothrombin time, partial thromboplastin time and platelet count. addison’s disease or underactive adrenal glands can cause hyper pigmented patches on skin, and mucosa like freckles on face, forehead, shoulders, nipples, lips, mouth, rectum, vagina etc. hope this helps. Take care.