You have not described the nature of the rash nor is the photo available but nonetheless the most common causes for rash on the face would be allergy and acne.
Azelaic acid (FINACEA Gel), 15%, is indicated for topical treatment of inflammatory papules and pustules of mild to moderate rosacea.
Rosacea begins as erythema (flushing and redness) on the central face and across the cheeks, nose, or forehead.
As rosacea progresses red domed papules (small bumps) and pustules can develop and this can be confused with acne.
You can try low doses of isotretinoin, which can help in clearing the lesions of Rosacea and acne.
Since you feel the lesions are worsening, you either need to stop the application of Azelaic acid or supplement it with oral anti-biotic like (tetracycline, doxycycline, minocycline) which is the first line of treatment for Rosacea.
Dear Doctor Aparna,
Thank you for your kind reply. I actually uploaded a photo. But still showing "Photo pending admin approval". Don't know how long will it take for the approval. The photo of the rash was sufficiently self explanatory.
Anyway, by this time she started taking anti-biotic and it improved her situation little bit.
After requesting the moderator, now the photo can be viewed. Can you please check it and comment on this?
My first question is whether it is Acne, Rosacea or something else? My sister is suffering from this rash for the last 6 months. She used to use pevisone cream. It reduced inflamation but never cured her completely. This time a doctor suggested her to use "azelaic acid 20%". When using it with anti-biotic now the rash get's better, but yet not 100% cured. We are ready to give it couple more weeks time. But we want it to be cured completely and never come back.