Would you be able to post a picture of the rash ?? It does not itch? Is the rash red ? Is the border smooth? Any scaling ? How long has this been going on ?? How soon after the use of the preponderant has this developed?
So far it sounds that he may have an adverse or allergic reaction to the deodorant... .Other cases may need to be considered such as perhaps a case of Candida dermatitis which is common in this area in general ...
Your history makes this sound more as an adverse reaction to the spray though ...
If itching then he may benefit to take oral antihistamines ( Example may be Zyrtec = generic certrizine 10 mg (it is over the counter) in the AM and Benedryl 25 to 50 mg at bedtime..
He may benefit to apply 1 percent hydro-cortisone twice day over the next week or ten days >>
I do think the area is so often affected by Candida Dermatitis that applying a nysatin based cream twice a day may be a helpful step if this is culprit or clotimazole cream twice a day
It is probable that if treats as above to cover both 1) possible contact dermatitis which is an allergic type reaction and 2) possible fungal infection of the skin >> esp Candida dermatitis would seem more likely to fit the description.. then I would more expect that he should steadily improve over the next 5 to 7 days or so..
You are welcome to load a picture to this page and that may help to better evaluate this problem..
He may certainly benefit to see his primary care doctor or dermatologist if he has ongoing symptoms of this rash..
I hope that this information is helpful for you. Let me know if you have further questions or discussion. I will be happy to get back wtih you! If my answers have been helpful and to your satisfaction then please remember to leave positive feedback. Thank You and Best Regards,
Anthony Bray MD