<qa>  What is the name of the most common irritating substance that causes VCD?One of the most common irritating substances that cause VCD is urine. The phenomenon of urine-induced VCD is known as diaper rash in babies, and it was also described in bedridden patients using diapers constantly. Women with urine incontinence UI, a problem that its prevalence in women increases with aging, may use constantly panty liners or pads to prevent urine leakage. The urine is being absorbed in the pad, and the vulvar skin is continually exposed to urine. This can cause VCD, similar to diaper rash. The prevalence of this phenomenon in the general population is unknown. 