Niacinamide If you clearly have an allergy, you must try to avoid contact with niacinamide ingredients in the future. One of the most important treatment principles in the management of skin allergies is to avoid allergens as much as possible. Before applying skin care products and cosmetics, it is best to check the absence of niacinamide in the ingredients before use. If a patient is suffering from a niacinamide skin allergy, he or she can immediately take antihistamines such as loratadine, cetirizine, paracetamol, ibastine tablets, and fexofenadine. Generally, one of them can be taken orally, but if it is more serious, two of them should be taken at the same time. If it is more serious, it can be taken orally with vitamin C. It is necessary to go to the hospital to apply glucocorticoids intravenously and calcium gluconate intravenously for relief.