Cockroaches are nocturnal insects that adapt easily to a variety of environments. They live in all types of houses and buildings. The proteins present in the bodies of cockroaches, their saliva, and their waste trigger allergies in us. These proteins can easily spread throughout homes, much like dust. Cockroach allergies are one of the most common indoor allergies. Nearly 60% of homes contain cockroach allergens, so there is year-long exposure to these allergens. People with certain genetic types are at a higher risk of being allergic to cockroaches and may experience symptoms like red eyes, skin rash, cough, runny nose, or asthma.

Milk allergy occurs when the body's immune system recognizes milk proteins as foreign and triggers an immune response. The symptoms of milk allergy usually begin within a few minutes to a few hours after the consumption of milk. This type of food allergy is identified during infanthood, but most children will outgrow it. Common risk factors for risk allergy include atopic dermatitis, family history, and age. Individuals of certain genetic types are at a higher risk of being allergic to milk and may experience symptoms like abdominal cramping, wheezing, hives, itchy skin, and diarrhea. Babies with this condition may also be colic.

Hay fever (Allergic Rhinitis) can be triggered by several allergen. It is characterized by cold-like symptoms; stuffy nose, nasal congestion, itchy and watery eyes. According to the Centers for Disease Control and Prevention (CDC), hay fever affects close to 18 million Americans. A common outdoor trigger for hay fever is pollen from trees, grass, weeds, and mold spores. Pet dander, dust mites, and mold are a few indoor triggers. People of certain genetic types are at a higher risk of having hay fever and may experience symptoms like runny nose and other symptoms similar to a common cold but with red and itchy eyes.

Dust mites are tiny creatures that commonly live in the house dust. According to the Asthma and Allergy Foundation of America, dust mites are among the most common triggers for year-round allergy and affect around 20 million people in the U.S. Dust mites feed on dead skin cells that humans shed every day - on average, we lose about 40,000 dead skin cells per minute. People of certain genetic types are at a higher risk of being allergic to dust mites and may experience symptoms like sneezing, runny nose, red eyes, skin rash, cough, or asthma.

Motion sickness (kinetosis or travel sickness) is characterized by feelings of dizziness and nausea. Motion sickness occurs when the inner ear, body, and eye send signals (about movements) to the brain that are conflicting. For instance, when traveling by plane, your eyes may not "see" the turbulence, but the rest of your body can feel it and thus may send opposing signals to the brain. Some risk factors for motion sickness include gender (female), sleeplessness, a history of migraine, and alcohol usage. People of certain genetic types are at a higher risk of having motion sickness and may experience symptoms like nausea, fatigue, and dizziness.

Pollen allergy is one of the leading causes of hay fever. It is also known as "seasonal allergic rhinitis" as it is common in spring, summer, and fall seasons. The immune system of the host recognizes pollen grain as foreign and triggers a strong reaction, leading to classic symptoms of pollen allergy. Most of the pollens that cause allergic reactions come from trees, weeds, and grasses. Some people tend to have pollen allergies all around the year. People of certain genetic types are at a higher risk of being allergic to pollens and may experience symptoms like an asthma attack, conjunctivitis, or a stuffy nose.

Pet allergy is an allergic reaction to the proteins present in the animal's hair, saliva, urine, or skin cells. According to the American Academy of Allergy Asthma and Immunology, 62% of households in the U.S. have pets. Pets tend to shed dead skin and hair, which can accumulate in all corners of the house. Though any animal with fur can trigger allergic reactions, most pet allergies are associated with cats and dogs. People of certain genetic types are at a higher risk of being allergic to pets and may experience symptoms like sniffling, itchiness, sneezing, and watery eyes.

Tree nut allergy is a hypersensitive immune reaction towards tree nuts and edible tree seeds. Walnuts, cashew nuts, almonds, lychee nuts, pistachios, or pecans could trigger an allergy. You can be allergic to one or more types of tree nuts. Tree nut allergy is one of the most common food allergies in both adults and children. Being allergic to peanuts increases your risk of being allergic to tree nuts. People of certain genetic types are at a higher risk of being allergic to tree nuts and may experience symptoms like asthma, itchy throat, skin rashes, swollen eyes, diarrhea, difficulty in swallowing, and shortness of breath.

Grass allergies are due to the pollen that plants create. These are scattered by the wind as opposed to pollens that are dispersed by the insects. This increases the risk of these allergens being inhaled. Grass pollen is released during the late spring and early summer. According to the Centers for Disease Control and Prevention (CDC), 19.2 million adults and 5.2 million children in the United States had hay fever in 2016. People of certain genetic types are at a higher risk of being allergic to grass and may experience symptoms like itchy eyes, stuffy nose, and a cough.

Nearly 3 million people in the U.S. have peanut and tree nut allergy. For people with peanut allergy, consuming even the tiniest amount of peanuts can cause a serious life-threatening reaction. A 2017 study reported that peanut allergy in children had increased 21 percent since 2010. Researchers from Mount Sinai School of Medicine (New York) have shown that genes account for 81.6% of the risk for peanut allergies. People of certain genetic types are at a higher risk of being allergic to peanuts and may experience symptoms like an itchy mouth, a tingling sensation, runny nose, congestion, or anaphylaxis.

Egg allergy occurs when the body's immune system recognizes egg protein as foreign and triggers an immune reaction. Egg allergy is the most common food allergy in children; as many as 2 percent of children are allergic to eggs. However, most children outgrow this allergy. The symptoms of egg allergy usually begin within a few hours of consuming egg. Common risk factors for risk allergy include atopic dermatitis, family history, and age. People of certain genetic types are at a higher risk of being allergic to eggs and may experience symptoms like hives or skin inflammation, nasal congestion, asthma, nausea, and vomiting.

Histamine intolerance occurs when too much histamine builds up in the body. Histamine is present in our stomach, skin, and lungs. Normally, excess histamine is degraded rapidly by two enzymes, histamine N-methyltransferase (HNMT) and histamine-degrading enzyme diamine oxidase (DAO). However, some factors can interfere with how DAO and HMNT work or how much of these are present. Maintaining a histamine-free diet can provide relief from histamine intolerance symptoms. This includes giving up alcohol, which interferes with the functioning of the DAO enzyme. Individuals with certain genetic types are at a higher risk of having histamine intolerance and may experience symptoms like headaches, dizziness, abdominal cramps.

Misophonia, which means "hatred of sound," is characterized by an extra sensitivity to common sounds like that of chewing food or gum, munching, the clicking of a pen, sipping drinks, and footsteps. People who suffer from misophonia tend to isolate themselves in order to avoid these noise triggers. They also tend to experience feelings of anxiety, rage, and panic upon being exposed to these sounds. This condition usually begins during late childhood. People of certain genetic types are at a higher risk of having misophonia and may experience symptoms like feelings of rage, an intense feeling of flight, with some people becoming emotionally explosive.

Also called ACHOO (Autosomal Dominant Compelling Helio Ophthalmic Outburst), photic sneeze reflex affects 18-35% of the U.S population. When moving from darkness to light, the part of the brain that processes light is over-activated in some people, resulting in repeated sneezing. A photic sneeze is different from a normal sneeze, which is caused by an irritant or an infection. It is a genetic condition and a dominant one too! This means if one of your parents has a photic sneeze reflex, then you are at a 50% chance of having it. People of certain genetic types are at a higher risk of having photic sneeze and may experience uncontrolled sneezing in response to stimuli (light).

Contact dermatitis is a type of eczema (red itchy rash) triggered by contact with a particular allergen. Symptoms occur within a few hours of exposure. The rash isn't contagious or life-threatening, but it can be very uncomfortable. The location of the rash depends on the allergen exposure. A high proportion of individuals affected by this condition are industrial workers in health, skin-care, beauty, food industry, and metal-related occupations. This skin problem occurs in 15% to 20% of people. People of certain genetic types have a higher risk for contact dermatitis and may experience symptoms like redness, itching, blisters, and occasionally, dry and scaly skin.