I know the subject well since I have dealt with this issue head-on. It is essential, like with my wife Kimberly A Frechette, who has Behavioral Variant Frontotemporal Dementia Stage 2, that I take control of her body for her, as hygiene will not be on her radar. This will go for both men and women, but women will get worse results, especially under their breasts, if they are not dry before putting on clean clothes.
The areas of concern are under the breast, the skin folds, which most likely are in the stomach area, and the groins. There are many other areas on the body where moisture can be trapped. The goal is to stop the skin-to-skin friction (rubbing) that will be intensified by the heat and moisture and cause inflammatory skin conditions.
The trapped moisture from sweating causes the skin to stick together, damaging the surface. Damaged skin allows bacteria and fungi to grow and multiply, triggering the immune system to respond. This results in secondary inflammation and a visible rash, or, in my wife’s case, a second-degree burn under her breast. This was very painful, and it required us to visit her primary doctor for medical attention.
My advice is never to let this happen in the first place. Every morning, I spend an hour with Kimberly checking her body over, followed by patting her body down to remove the moisture. Then, I rub her body with cornstarch powder, especially areas where the skin touches the skin, like under the breast, stomach skin fold, and armpits. I also put hydrating lotion on her arms and legs before I dress her. Lastly, I put foot cream on her feet and between her toes.
Word of caution to those male caregivers who are taking care of a spouse with dementia—it will be natural for you to get aroused when rubbing their body down—you will have to learn to control any temptation physically (sexual advances) toward your spouse. Your job is to be a caregiver and take care of her body so she feels good about herself. Not to pleasure yourself in the process—bottle your feelings!
When I have Kimberly entirely dressed, I give her Miracle, her favorite perfume. She applies it to her inside wrist and rubs the two together. This makes her feel like a woman even though her mindset is that of a 3-to 5-year-old!