A drug allergy is an adverse reaction to sensitivity towards drugs and medications and it doesn’t include the immune system most of the times. Medications and therapies like Antibiotics, Aspirin, non-steroidal anti-inflammatory medications, Anticonvulsants, Monoclonal antibodies, Chemotherapy are more likely to produce allergic reactions. One of the most severe allergic reactions is  Anaphylaxis that involves hives, lowered blood pressure, swelling, and in more severe cases, causes anaphylactic shock, which if not treated immediately can be lethal since it involves more than one body metabolic functions. However, an allergic reaction doesn’t occur on the first exposure with the allergen, since the body has to first create memory then the lymphocyte cells make antibodies against the antigen. However, since the drugs consist of numerous different substances, any of those substances can cause an allergic reaction, including dyes. Symptoms include rashes, trouble breathing, fever, itching, and swelling or redness.

The vaccine allergy is one of the most extremely rare types of allergy, with only one to two serious allergic reactions per million vaccinations given. But when a person affected by vaccine allergy, it can be very serious, even life-threatening. The allergic reactions start within minutes, after the vaccination and the symptoms include indications on the skin like itching, urticaria, and swelling, followed by respiratory indices like a cough, wheezing, difficulty breathing, swollen glands, and a reduced blood pressure. If the reaction is stronger, then it should be treated immediately with epinephrine.

Food allergy is an immune system reaction that occurs due to certain proteins found in food. Even a tiny amount of allergy-causing food can trigger signs and symptoms such as hives or swollen airways, digestive problem. In a few people, a food allergy can cause severe symptoms or even can be frightening such as anaphylaxis which is a life-threatening reaction. Food allergy affects an estimated 5 to 7 percent of children under age 3 and up to 3 percent of adults. While there’s no cure, few children grow with their food allergy as they get older. Food allergy includes itchiness, vomiting, diarrhea, hives, trouble breathing, swelling of the tongue, or low blood pressure. Food allergies are more common in male children than females and appear to be increasing in frequency. Some allergies are commonly developed in early life, while others typically develop later in life.

Microbial allergy: A misguided reaction to foreign substances by the immune system, the body system of defense against foreign invaders, particularly pathogenic microorganisms, bacteria, fungi, protozoa, worms, virus and even infectious proteins called prions. The allergies can cause bacterial infections including sinusitis whereas many sinusitis infections are viral and resolve on their own; which cannot be treated with the antibiotics. However, the bacterial sinus infections may require antibiotics to get better. The symptoms of sinusitis can include nasal drainage or congestion, lessened ability to smell, facial pressure, fever, fatigue disorders, cough, and ear pressure. People with these symptoms may have a bacterial infection. Many antibiotics are highly effective against bacterial sinusitis, wiping out the infection.

Stings from the insects such as hornets, wasps, honeybee, yellow jackets, and fire ants are known to cause the allergic reactions to the venom injected into the skin. However, most of the people are not allergic to the insect venom, but sometimes the pain from the sting may cause them to mistake a normal reaction for an allergic one.  The harshness of an insect sting reaction differs from person to person based on the types of insect toxins. A normal reaction will result in swelling, pain, and redness confined to the sting site. But a large-scale reaction will result in swelling that extends beyond the sting site which can persist for two to three days, corticosteroids and antihistamines are sometimes prescribed to lessen the discomfort. During the summer and spring months, people with allergy are not the only ones wary of wasps, bees, other insects. These belong to the Hymenoptera order of insects, and their stings cause itching and painful swelling in non-allergic individuals.

Pathophysiology or physiopathology of allergic diseases is a convergence of pathology with physiology; which can assist in the treatment, management, and therefore in the prevention of allergy. Allergic diseases may develop in any organ or system which is caused by the etiological factors includes infectious agents and foreign proteins of the factors operating in the casual pathogenesis of infectious diseases. The most important one is an exaggerated formation of antibodies, which appears to be uncontrolled and occurring irrespective of the demands of the organism. The crucial morphological features in allergic inflammation are rather assorted, their diagnostic value differing in a wide range but being never absolute. The immunoperoxidase and immunofluorescent methods and electron microscopy are important diagnostic tools which have been generally acknowledged that many drugs operate as antigens. This may cause the death of the respective patient, but the allergic manifestations may subside after withdrawal of such drugs.

The skin is the largest organ of the body which plays an important role to protect your body from infection. Sometimes the skin itself becomes infected which is caused by a wide variety of bacteria, virus, fungus, germs, and symptoms can vary from mild to serious. Mild skin infections may be treatable with over-the-counter medications and home remedies; whereas other infections may need medical attention.  Bacterial skin infection starts with small and red bumps that slowly increase in size. Few bacterial infections are mild and easily treated with tropical antibiotics, but other infections need an oral antibiotic. Fungal infections of the skin are very common and include athlete’s foot, ringworm, jock itch, and yeast infections. Virus-related cutaneous conditions are caused by two main groups of viruses- RNA and DNA types-both of which are obligatory intracellular parasites.