Can I use nystatin and triamcinolone acetonide cream to treat a rash caused by allergy to roaches?

Depends. Nystatin is used to treat fungal infections. Triamcinolone is topical steroid, which is used to treat eczema or allergic contact dermatitis type reactions. I f the rash is being caused by an allergic reaction, using the triamcinolone cream twice daily on the affected area will help. However, roaches traditionally causes nasal allergy symptoms or worsening of asthma and rarely contact reactions.