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 should not be confused with methyl blue, another histology stain, new methylene blue, nor with the methyl violets often used as pH indicators. Methylene blue is a heterocyclic aromatic chemical compound (a phenothiazine derivative) with the chemical formula C16H18N3SCl.