Diclofenac is one of the commonly used drugs belonging to the family of nonsteroidal antiinflammatory drugs (NSAIDs). It is used to treat mild to moderate pain works by reducing substances in the body that cause pain and inflammation. Hypersensitivity reactions against diclofenac can manifest as Type I-like allergic reactions including systemic anaphylaxis. To protect the body from this perceived threat, or allergen, the immune system of an allergic person produces antibodies called immunoglobulin E. Specific immunoglobulin E (IgE) test is conducted to check if the person is allergic to a particular allergen, in this case, the drug diclofenac.