Cockroach Allergy

A cockroach allergy is a common trigger of year-round allergy and asthma. If you are allergic to them, they can trigger asthma attacks.

Between 78% and 98% of homes in urban areas have cockroaches. The cockroach represents one of the most common sources of indoor allergens worldwide, and 40%-60% of patients with asthma in urban and inner-city areas possess IgE antibodies to cockroach allergens.

Cockroaches are Nocturnal Insects

Cockroaches are insects that live in many locations around the world. Of over 3500 identified species only a few are of importance to people because they have adapted to living in buildings.

These pests adapt easily to a variety of environments. They are pests because of their filthy habits and bad smell. Pest cockroaches live in close association with people. They prefer warm conditions found most often in buildings. Cockroaches usually live in groups.

They are mostly active at night; in the daytime they run away from light and hide in cracks and crevices in walls, door frames and furniture, and in secure places in bathrooms, cupboards, steam tunnels, animal houses, basements, televisions, radios and other electric devices, drains and sewer systems.

What Do Cockroaches Eat?

Cockroaches are omnivorous scavengers and will consume any organic food source available to them. Cockroaches eat a great variety of food, including all food used for human consumption. They prefer starchy and sugary materials. They sip milk and nibble at cheese, meats, pastry, grain products, sugar and sweet chocolate. They also feed on cardboard, book bindings, ceiling boards containing starch, the sized inner lining of shoe soles, their own cast-off skins, dead and crippled cockroaches, fresh and dried blood, excrement and sputum.

Cockroaches will eat fingernails and toenails of babies and sleeping or sick persons, skin, and hair, including eyelashes. The nails, hair, and skin contain protein. But these items are not highly desirable foods for a cockroach. A cockroach might try to nibble on your fingernails or the dead skin on your feet or hands if it was desperate.

Cockroach Allergy in Children

Children are more susceptible to cockroach allergies than adults. Sensitization to cockroach allergens has been linked to the development of wheezing in young children. Cockroach allergen levels have also been directly linked to poorer asthma outcomes in inner-city children with asthma, including increased asthma-related healthcare utilization. Children who are allergic to cockroaches, and are exposed to them, need to go to the hospital for asthma more often than other children with asthma. Inhalation of cockroach extract caused a significant decrease in lung function for asthmatic subjects with a cockroach allergy.

Genetic Basis for Cockroach Sensitization

While there appears to be a rather clear relationship between allergen exposure and allergen sensitization, the dose-response relationship is most relevant for “susceptible” inpiduals. Conversely, the majority of inpiduals, when exposed to very high concentrations of allergen, never become sensitized. Cockroach sensitization is not a function of cockroach allergen exposure alone, and that genetic susceptibility may be important. Indeed, significant familial aggregation of allergic sensitization to cockroach allergen has been observed.

Aerosolized proteins derived from their saliva, fecal materials, secretions, cast skins, debris and dead bodies of cockroaches produce indoor allergens and can induce IgE mediated hypersensitivity reactions and allergic disorders.

Cockroach Allergens and Co-Sensitization

Tropomyosin is an important major allergenic cockroach protein involved in cross-reactivity among insects, mites, crustaceans, mollusks, and parasites. It has also been found as a major allergen in shrimp and also in other crustaceans, mollusks and dust mites.

Symptoms of Cockroach Allergy

When cockroach exposure occurs in early infancy, wheezing and asthmatic attacks are often the main consequences in allergic infants. Symptoms of cockroach allergy range from allergic rhinitis, with predominantly nasal symptoms, to asthmatic wheezing leading to more episodes of hospitalization and absenteeism from work.

Common cockroach allergy symptoms include: sneezing, runny nose, itchy, red or watery eyes, stuffy nose, itchy nose, mouth or throat postnasal drip ,cough , itchy skin or skin rash.

If your cockroach allergy triggers your asthma, you may also experience: difficulty breathing, chest tightness or pain, a whistling or wheezing sound when breathing out, trouble sleeping caused by shortness of breath, coughing or wheezing.

Distinctive Characteristics of Cockroach Asthma

Typical characteristics are identified from cockroach-allergic patients with asthma, when compared with those with ragweed asthmatics and asthmatics in general. A history of perennial asthma, possibly worse in the winter is the most common clinical presentation of asthmatic patients with cockroach allergy. Patients with cockroach allergy have particularly high levels of serum IgE antibodies as compared to general asthmatics patients. Steroid dependency of cockroach asthma is higher (32% of the patients) than those of general asthmatics. As a result, cockroach asthma is a severe allergic asthma which needs more attention.

Mechanism of Allergy

In the past 20 years, the identification of twelve groups of cockroach allergens has enabled studies on allergen-specific mechanisms of action. Cockroaches produce a variety of sensitizing proteins. The risk of developing asthma is maximum when a high exposure to cockroach allergens is associated with cockroach allergy. Neither of these factors is responsible for asthma by itself. When cockroach allergens were inhaled, bronchoconstriction occurred in such patients.

Proteases are proteolytic enzymes or peptidases that break the long chainlike molecules of proteins into shorter fragments (peptides) and eventually into their components, amino acids. Protease allergens are known to enhance allergic inflammation. Sources of allergens, such as pollen, house dust mites, cockroaches, and fungi, may produce or contain proteases and thereby activate and disrupt the epithelial barrier, causing greater sensitization.

Proteases in cockroach remnants may degrade the epithelial barrier in the human airways, allowing for easier penetration of the allergens and immune activation. Both innate and adaptive immunity is involved, resulting in a full-scale hypersensitivity reaction.

Cockroach allergy may be modulated by genetically determined susceptibility, which may be the reason why all people exposed to high levels of cockroach allergens do not develop cockroach allergy.

Early, consistent, and intensive exposure to cockroach proteins, especially in early life, results in asthma and allergies. Thus, children with a positive skin test are three times as likely to be hospitalized, to require more visits to healthcare professionals, and to miss more school days than non-allergic children living in the same environment. Results of a recent inner-city birth cohort study showed that prenatal exposure to cockroach allergens was associated with a greater risk of sensitization by the age of 5 to7 years.

Tips to Avoid Cockroach Exposure

Avoid exposure to cockroaches and their droppings. Pests need food, water and shelter to survive. There are changes you can make to your home to reduce the numbers of these unwanted “guests”: cover all trash cans tightly and store food in airtight containers, this includes food kept in cabinets and on counters. Clean all dirty dishes. Do not leave them in the sink or on the counter.

Sweep up any food crumbs from the counters, stove top, tables and floor. Wipe up any spills. Vacuum and mop floors regularly. Avoid leaving pet food out in a bowl. Clean the bowl regularly, like other dirty dishes. Fix leaky pipes under sinks and in the basement. Cockroaches like damp places. Seal cracks in the walls and floors where cockroaches can enter your home. Use cockroach baits and traps. Don’t use sprays. They can irritate allergies and asthma.