Nickel allergy is a skin rash or irritation that occurs when you come into contact with nickel. This condition is a form of allergic contact dermatitis. Allergic contact dermatitis happens when your skin touches or comes near an ordinarily harmless substance. Nickel allergy is the most common type of contact dermatitis related to metal. The skin rash from nickel allergy may be …

Peanut allergies happen when your body mistakes peanut protein for something harmful. Your immune system responds by causing an allergic reaction, which could include hives, vomiting and swelling. Peanut allergies are the most common food-related cause of anaphylaxis, which can lead to swelling in your airways or a severe drop in blood pressure. Call 911 (or your local emergency service number) or get to an …

A penicillin allergy occurs when your immune system reacts negatively to the antibiotic penicillin or an antibiotic in the penicillin family (beta-lactam antibiotics). Penicillin is a medicine that treats infections. When you take penicillin, the medicine destroys the outer wall of bacterial cells. This ultimately kills and removes a bacterial infection from your body. Just because you have a penicillin allergy today doesn’t …

Pet allergies are certain proteins — called allergens — on your pet that cause your allergic immune system to overreact. These allergens are in animal fur, skin, urine (pee) and saliva (spit). It’s also in pet dander, which is tiny scales from your pets’ skin, hair or feathers. Usually, these proteins are harmless. However, your allergic immune system views them …

A shellfish allergy is a type of food allergy. Shellfish are animals that live in the water and have a shell-like exterior. There are two types of shellfish: Crustaceans: shrimp, crayfish, crab, lobster. Mollusks: clams, scallops, oysters, mussels. What fish is shellfish? If you have a shellfish allergy, don’t eat these ingredients and foods: Abalone. Clams (such as cherrystone, littleneck, pismo, quahog). Cockle. …

A wheat allergy is one of the most common types of food allergies. Your immune system overreacts to wheat you’ve ingested (eaten or drunk) or inhaled (breathed in). For many people, ingesting wheat is harmless. However, if you have a wheat allergy, your immune system views wheat as a harmful “invader,” like a bacterium or virus. A wheat allergy can be deadly. If …

Most healthy people lose up to 100 strands of hair per day. As part of your hair’s growth cycle, new strands grow and take the place of the ones you shed. When you start to shed more strands — and fewer or none grow back — the condition is considered alopecia (hair loss). There are several types of hair loss, and it …

Alpha-gal syndrome (AGS) is a serious and unusual food allergy to red (mammalian) meat. It occurs in people who have been bitten by certain types of ticks, usually if they’ve been bitten more than once. Ticks are mite-like parasites that feed on blood. The saliva of some ticks contains a sugar molecule called alpha-gal (α-Gal). When alpha-gal enters the bloodstream, it can …

ALS, or amyotrophic lateral sclerosis, is a neurodegenerative condition that affects the nerve cells (neurons) in your brain and spinal cord. It targets your motor neurons. These regulate voluntary muscle movements (like the ones you use to talk, chew and move your arms and legs) and breathing. Your neurons communicate with your muscles to tell them to move. ALS disrupts the communication, like bad phone reception. The …

Dry socket (alveolar osteitis) can happen after tooth extraction. When your dentist or oral surgeon removes a tooth, a blood clot forms in the socket (a hole in the bone where your tooth was). Dry socket happens when that blood clot dislodges (moves) or doesn’t form at all. Without the clot, your bone and nerves become exposed, leading to pain and slower healing. How common is dry …