I am Dr. Prasad Akole (Critical Care Expert- http://bit.ly/Dr-Prasad-Akole) and am glad to address to your query here.
Drug rashes due to allergy
can occur due to any drug as they are foreign proteins
Is the rash itchy? Raised weals?
Have you previously taken any metronidazole
or that category of medicines?
Which parasitic infestation do you have?
Be watchful for breathlessness, itchiness, giddiness…. Signs of an allergy.
If there is rapid worsening, stop the drug and seek medical attention.
I hope you are fully satisfied with the guidance I gave.
I would be glad to answer any further queries. Please ask for any clarifications before closing and rating this answer.
Thank you and Good luck!