Drug Hypersensitivity- Drugs can act as allergens and cause allergic reactions. The route of adminerstration can influence how the reaction will be manifested and its severity. Topical drugs can cause a greater reaction than oral or parenteral. Patients with multiple allergies are more likely to have an allergic reaction to drugs. Patients with with autoimmune diseases commonly have adverse reactions to medications. Children with strong levels of immunity are less likely to have an allergic reaction. Drugs can be invovled in any types of hypersensitivity. Type I hypersensitivity to drugs includes anaphylaxis, urticaria, and angiodema. An example of type III hypersensitive is serum sickness- This is when a reaction that occurs frequently when patients were given a large amount of antitoxin serum from horses to provide passive immunity in the treatment of diphtheria and tetanus. This is no longer a method for passive immunity. Penicillin is the most common cause of serum sickness. The signs and symptoms of serum sickness are rash, fever, painful swelling of the joints, Renal disturbance or failure, edema around the eyes, and cardiac inflammation. Drugs can also be involved in Type IV hypersensitivity. This reaction can occur from topically applied substances and can produce contact dermatitis, and mucositis.
