Hello,
Iron deficiency anemia, thyroid disease and connective tissue disorders can cause dry, itchy skin and joint pains and easy bruisiability. Other than that it can be due to contact dermatitis, allergic reaction, lupus or scabies (less likely).
Get your blood investigations done and apply some calamine lotion at the rash as it will help in soothing the skin. Also take some antihistaminic like Benadryl and apply a mild steroid cream on the itchy bumps.
If the symptoms persist then get an evaluation done from a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Impotrant to rule out connective tissue disorders especially bearing in mind the bruising and pains. Could well be a drug rash.