Dear anil,
Well, i have been thru such one case once, the only way to help this girl, is by means of hypnotism, we have to take this gril into deep trance and after that, we have to question her about this obbessive tnedency, i am sure some adult female must have sexually harrased her, due to which she has a psycological flaw, where she feels that due to that "sexual incident", she is dirty and now, everynow and then,she uses dettol to clean herself, after touching any female, i think we have to reprograame his sub-conscious mind with this isntruction that this is absolutely normal, and she wont get dirty just by touch of a women......
So contact a nice doctor who can hypnotise her and then further re programme her sub conscious mind.
Lord shiva bless her
Nalin M.