I recently developed a psoriasis condition. The dermatologist said it was the citrus shampoo I was using that caused it. I've used the same shampoo for many years. I started thinking about a nickel allergy I have and looked up nickel-containing foods. BINGO! Nickel is in coffee, canned goods and beans, for example. I switched shampoos just to be safe. I purchased one on Amazon called Honey skin. It worked like a charm. The inflammation is very low now.