DVT is a blood clot that forms in a major vein of your body, most commonly in your legs. It can also occur in your arms. * Swelling in the affected leg or arm, which can include swelling in the foot or ankle. It is most typically in one leg or arm.
Allergen immunotherapy is appropriate for patients suffering from immunoglobulin E (IgE)âmediated allergic diseases such as seasonal allergic rhinitis, perennial rhinitis, allergic asthma, and insect venomanaphylaxis.
1 An allergen is a substance that your body perceives as dangerous, which causes an allergic reaction. 2  An antihistamine is a medication that prevents congestion, sneezing and itchy, runny nose by blocking histamine (a substance released by your body's immune system after being exposed to an allergen.