Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
My thoughts and suggestions are as below.
Coughing,
fever, sore ankle, wrist and knee joints along with development of
skin rash that is not elevated can be due to one of the following reasons:
Viral as your have mentioned and has no specific treatment.
Elevated AST, low white cell count all indicate the same.
The treatment is symptomatic like
paracetamol for fever, anti-histaminics for rash, multivitamins and mineral supplements for an early recovery.
Consult a Doctor for clinical evaluation, examination and order for any further investigations and have proper prescription based management.
Hope I have answered your query.
Let me know if I can assist you further.