As unusual as it may seem, cockroach allergy is a real thing! It is a common trigger of year-round allergic and asthmatic symptoms, as cockroaches contain a protein that is an allergen for many people, which will induce an allergic immune reaction.¹

It is widely prevalent in today’s society, as a recent study identified that cockroach allergy ranges between 17% to 41% in the US, with cockroach allergens being detected in 85% of inner-city US homes.² As cockroach allergy creates respiratory symptoms and skin reactions that are similar to seasonal allergies, it is difficult to differentiate between them, so it is often mistreated or undiagnosed.

Continue reading to educate yourself on cockroach allergy.

Understanding cockroaches

Cockroaches can easily be identified by their flattened oval shape, small heads with chewing mandibles and a plate that protects their head from above. They play a vital role in their ecosystems as they are detritivores, where they recycle nutrients in rotten food matter. They are also a main source of food for many creatures, such as birds and rodents.

There are roughly 4,500 species of cockroach, but only a handful of these species live in people’s homes and have been researched in association with allergies in humans. These include the American cockroach, German cockroach, oriental cockroach, brown-banded cockroach and smoky brown cockroach. The former two are the most predominant species that infest human dwellings and cause allergies.³

Cockroaches prefer dark, warm, and moist environments, but they can be found in cities, forests, deserts, and bodies of water.⁴ They are gregarious insects as they stick together in families where their colonies are multigenerational, which means their group numbers grow exponentially.

Allergenic properties

Cockroach allergens are derived from their droppings, shredded skin, body parts and saliva. It is the proteins within these products which cause harm to humans once inhaled or ingested. Be aware that these allergenic properties can become airborne when being attempted to be removed by vacuuming.

Cockroach allergy symptoms

The symptoms of cockroach allergies are similar to other common allergies, such as seasonal allergies, dust, and mites.¹ These symptoms include both respiratory and skin symptoms, predominantly:

• Sneezing
• Runny nose
• Sore throat
• Itchy, red, or watery eyes
• Itchy skin
• Skin rash

If you have these symptoms all year round, it is a real possibility that you suffer from cockroach allergy.

If your cockroach allergy triggers your asthma, you may also experience:

• Difficulty breathing
• Chest tightness or pain
• Wheezing

Furthermore, an odd but common symptom of cockroach allergy is that you experience these allergic symptoms after eating chocolate or peanut butter. REF. In the production of these foods, it is difficult to filter out insects that have accidentally been incorporated into the product; therefore, once these food items have been ingested, you will suffer from the stated symptoms if you are allergic to cockroaches.

Diagnosis for cockroach allergy

To diagnose a cockroach allergy, your doctor will discuss your symptoms and living conditions to gauge whether cockroaches are likely to inhabit your home, as they are likely to reside in your rubbish bins.⁵ As the symptoms of a cockroach allergy can overlap with those of any common allergy, it can be difficult to get a diagnosis.

From your consultation with a doctor, if they believe that you have a cockroach allergy, they will give you a physical exam and refer you for allergy testing, which may involve a skin prick test or a blood test.

Below is an overview of the procedures.

Allergy tests

Either a skin prick test or a blood test will be conducted to determine if you are afflicted by a cockroach allergy.

Blood tests (RAST)

This will be conducted initially at the clinic to rule out other health ailments. Blood will be collected from the forearm and sent off to the lab to measure the amount of IgE antibodies in your blood.⁶ To determine what substance is triggering an allergic reaction, your blood will be tested against common allergens, as well as the specified cockroach allergy. Results in most cases will take a few days to process, and high levels of IgE antibodies will indicate an allergy.

Skin prick test

This produces the fastest results because if you are allergic to cockroaches, the reaction is close to instantaneous. This involves placing a small drop of the allergen onto your forearm and lightly scratching the skin so the allergen can react with your skin. Depending on the severity of the allergy, red marks could appear within mere seconds. These marks will then be measured to identify the best method of avoiding and managing the allergy.

Risk factors

You are more at risk of acquiring a cockroach allergy if you have a genetic predisposition to asthma. A study identified that exposure to these allergens appears to have the greatest effect on asthma morbidity than any other common allergy amongst inner-city children with asthma.² This is because they release allergens such as bla g 4, which aggravate the respiratory system.^7,8

Secondly, you are at risk of acquiring this allergy by living in climates with hotter temperatures, such as many parts of the US, where cockroaches thrive and multiply, so the likelihood of coming into contact with a cockroach is much higher. Geographically, cockroach-induced asthma is more likely to occur in areas that have substandard housing, regardless of whether rural or urban.⁹ Additional factors, including socioeconomic, climatic, and cultural differences, may influence the prevalence of cockroach infestations.

Managing life with a cockroach allergy

Once diagnosed with a cockroach allergy, unfortunately, you’ll have to make a few lifestyle adjustments. Examples of this can be accomplished by reducing exposure to allergens through cleaning and symptom relief by taking medications. Other lifestyle adjustments could be in the form of changes in routines, such as sleeping with your windows and doors shut once it gets dark, as that is when cockroaches are most active due to being nocturnal.

Prevention

The best way to invite cockroaches into your living space is through poor home hygiene. As pests need shelter, food, and water to survive, you should do the following to prevent cockroaches from invading your personal space:

• Take out your rubbish regularly
• Cover bins with lids
• Store food in airtight containers
• Wash cooking utensils and dishes promptly after use
• Clean and vacuum surfaces
• Avoid leaving pet food out
• Seal cracks in walls and floors

Using pest control methods such as traps and baits is also a good method of limiting exposure to allergens. If this isn’t working, you should consider hiring a specialist exterminator to implement an integrated pest management approach. It is important to note that you should avoid using sprays, as this could further irritate allergies and asthma.¹

Treatment

You will need to take medications to control allergy symptoms, as it is the most effective way of keeping symptoms at bay. Medications such as antihistamines, decongestants or corticosteroids may be prescribed to you by your doctor.

• Antihistamines: These are mainly available over the counter and are often used to relieve symptoms of allergies such as sneezing. These can be used as a preventative measure or to counter the effects when symptoms appear
• Decongestants: These are a type of medicine that provides short-term relief for nasal congestion. They shrink the lining of the nasal passages and relieve stuffiness¹
• Corticosteroids: These are the most effective medicine for allergic rhinitis because they reduce all symptoms, including nasal congestion
• Immunotherapy: These will be recommended to you by your doctor and will help you develop a tolerance to cockroach exposure¹⁰

Depending on the severity of your allergy, if you have been in contact with a cockroach and develop symptoms of anaphylaxis, you may have to use emergency management such as an EPI-PEN to treat them. However, this only occurs in rare cases, and your healthcare provider will make you aware.

Are there other allergens I could be sensitised to?

Individuals who are allergic to a specific cockroach can also be reactive to a different species of cockroach. Furthermore, studies have revealed that if you are allergic to cockroaches, you have a genetic disposition to become allergic to other creatures such as arthropods, insects, and arachnids due to proteins and substances within these creatures that are structurally similar to those of cockroaches.¹¹

Conclusion

Cockroach allergy can be a complex ailment to diagnose because not only can it be disguised by many other similar allergies due to the overlapping symptoms, but it is also an understudied sensitivity because only a few species have been studied concerning susceptibility in humans. Once you have approached your healthcare provider about your concerns, they will advise you to undergo lifestyle changes to manage these symptoms. This can be accomplished by routine changes, cleanliness changes and taking medication.