What Vitamin Deficiency Causes Purple Toenails? Separating Fact from Common Causes
                                
                                
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                                    5 min read                                
                            
                                While nail discoloration can sometimes signal a nutritional issue, a purple toenail is far more frequently caused by a simple injury or underlying circulation problem. However, a **vitamin B12 deficiency causes purple toenails** in some rare cases, manifesting as blue-black pigmentation or streaking.