Since you have undergone so many tests, I’ll just enumerate the various causes of multiple joint pain with rash. Well, joint pains with rash can be seen in SLE (lupus), psoriatic arthritis, fibromyalgia, polymayalgia rheumatica and chronic fatigue syndrome. Gout, though typically affects the great toe, can cause multiple joint pain with rash. Hashimotos Thyroiditis is another possibility. Hayfever and rheumatoid arthritis too should also be ruled out. Crohn’s disease is another possibility.
Another possibility is reactive arthritis, which could have occurred in reaction to something—in this case rash. In this case you need to rule out the cause for the hives or urticaria. Urticaria is usually triggered by allergens, such as drugs, foods, insect bites, inhaled substances, in response to sunlight, cold, heat, stress, exercise, or a viral infection. Other common allergens are pollen, mold, dust, pet dander, or cosmetics. Food allergies like to gluten and alcohol too should be looked into.You may need to consult an allergy specialist. Take care! Read More At : ...