Hello. Thank you for writing to us
I suggest a likely possibility of fungal infection/
intertrigo Or it could also be intertriginous
psoriasis considering that you have a history of psoriasis.
Body folds like sub-mammary area, groin etc trap moisture and warmth and therefore provide an Ideal environment for the fungus to grow.
Psoriasis too can affect body folds and presents as bright red patches with lot of itching and burning sensation.
If I was the treating doctor I would have started you empirically on a topical antifungal+steroid combination cream e.g
clotrimazole 1%+beclomethasone dipropionate 0.025% cream, twice daily.
The steroid part would take care of the inflammation i.e itching and redness whereas the fungal part would help control the fungus.
Moreover intertriginous psoriasis is a steroid responsive condition and topical steroids are drugs of choice for intertriginous psoriasis.
Since the affected area is quite large therefore I would also suggest an
oral antifungal e.g
fluconazole.
An OTC oral antihistamine e.g cetrizine 10 mg once daily will provide you symptomatic relief from itching.
Topical and oral antifungals need to be continued for 4-6 weeks.
Regards