Picture 1 â Sun Poisoning Rash. Source â prime health channel. When excessive exposure of the skin to the harmful UV rays of the sun causes an allergic reaction in the form of development of itchy skin rash and the reddening of the skin, one may be said to suffer from Sun Poisoning Rash.
Note that excess niacin intake can cause symptoms similar to an allergic reaction, including skin flushing, stomach redness and warmth, particularly of the face. Your physician may recommend allergy testing to determine if you have an allergy or symptoms of excess intake.
Niacin overdose is unlikely if you take niacin only in the amount prescribed by your doctor. While it's not possible to overdose on niacin simply by eating too many niacin-rich foods, taking too much over-the-counter or prescription niacin can be dangerous. Niacin overdose signs and symptoms include: 1  Severe skin flushing combined with dizziness. 2  Rapid heartbeat. 3  Itching. Nausea and vomiting.  Abdominal 1  pain. Diarrhea.  Gout.