Various conditions can lead to irritated, red skin. Causes can range from a temporary sensitivity to a chronic skin problem. Common culprits of red skin or red spots include: 1  Dry skin. 2  Sunburn. 3  Rosacea. 4  Acne. 5  Allergic contact dermatitis. 6  Eczema (atopic dermatitis).
Methylene blue is a component of a frequently prescribed urinary analgesic/anti-infective/anti-spasmodic known as Prosed, a combination of drugs which also contains phenyl salicylate, benzoic acid, hyoscyamine sulfate, and methenamine (aka hexamethylenetetramine and not to be confused with 'methanamine').
Methylene blue has been used clinically for over a century, but its association with serotonin toxicity has just been elucidated in the last decade. Two surgical case series from 2006 and 2007 describe methylene-blue associated CNS toxicity in patients receiving intraoperative methylene blue.