Re: yup, poison oak sucks
|Yup, sure does. I did a little up front research before answering your question, McGee, as I wanted to make sure I knew all the answers :-) (so is it my witty reparte or just the pointers to interesting facts...)
The issue with mango trees is that most folks don't know that the sap contains urushiol oil. What makes poison ivy, poison oak, poison sumac, mango trees, Brazillian pepper trees, and a host of others so toxic to you and I is the urushiol oil the plant contains. The mango tree (Mangifera indica) is a member of the Anacardiaceae family (the cashew family) along with a number of other plants including poison oak. The leaves, bark, stems and skin of the mango contain urushiol. Yikes!
So to answer your question, yes the rash will eventually go away. It's an allergic reaction (called allergic contact dermatitis or ACD) and until basically the body sloughs / rids itself of the irritant and then heals, you're stuck with the rash. Boy, itching does feel good though doesn't it? Been there, done that, got the marks to show for it. Scratching is dangerous as you may introduce bacteria into the open wound and cause an infection. This can then lead to scarring. Don't scratch (if possible).
The key to rash healing is to make sure you keep it clean and dry. Tecnu is good for removing the oil but once its bonded with the skin, urushiol is nearly impossible to get out. Scratching promotes skin sloughing and so you are removing bit by bit some of the skin with the urushiol bonded to it. Looking at low / no cost treatments to curb the itch, you might try an over the counter antihistimine (not topical). I've also read a number of positive notes about using ice packs and very hot water. Check out the treatments section on this site for more ideas.
In case you are wondering, I'm of the grin and bear it camp. I've tried a number of remedies both home and commercial with limited success. The last 2 or 3 outbreaks, I've just ignored the itch. Somehow I don't think I could ignore one that covers 90% of my body though.... Good Luck!