Study finds cockroach allergy often driven by shared proteins across arthropods

By Pooja Toshniwal PahariaReviewed by Susha Cheriyedath, M.Sc.Mar 13 2026

A new molecular analysis reveals that many patients labeled as cockroach-allergic may actually be reacting to shared proteins found across mites, seafood, and insects, highlighting the need for more precise allergy diagnostics.

Study: Cockroach sensitization and its hidden links to mite and food allergens. Image Credit: kaninw / Shutterstock

A recent study published in Scientific Reports found that allergic reactivity to cockroaches may reflect sensitization to a broader spectrum of cross-reactive allergens in patients with perennial allergic rhinitis (PAR).

Cockroach allergy often coincides with sensitivities to other arthropods, seafood, dust mites, and certain wasp species. Patterns of overlapping antigen responses vary by cockroach species, revealing distinct species-specific cross-reactivity patterns among allergens. These findings may improve personalized allergy profiling and support more targeted management strategies for patients with allergic rhinitis (AR).

Cross-reactive allergens complicate the diagnosis of cockroach-related allergic rhinitis

Cross-reactivity, in which the immune system responds to structurally similar allergens, plays a key role in allergic diseases and can worsen symptoms. Cockroach sensitization is a major trigger of AR and asthma and often occurs alongside reactions to house dust mites, seafood, and other indoor allergens.

Despite its clinical importance, research gaps remain regarding species-specific molecular sensitization patterns. Polysensitization is rising and affects more than 80% of allergic rhinitis patients, often leading to more severe symptoms. Understanding these patterns is essential for improving allergen-specific immunotherapy and guiding personalized management strategies, particularly for children and high-risk populations.

Researchers analyze molecular sensitization patterns in cockroach-allergic patients

Researchers investigated molecular patterns of cockroach sensitization in patients with PAR in Poland.

The study included 250 residents of Bialystok in northeastern Poland, with a mean age of 32 years (158 males and 92 females). All participants were referred to an allergy clinic and underwent skin prick testing (SPT) for common airborne allergens.

Tested allergens included house dust mites (Dermatophagoides pteronyssinus and D. farinae), cockroach (Blattella germanica), birch, mugwort, grass, dog, cat, and Alternaria. Results showed that 48 patients (19%) tested positive for cockroach extract and were selected for further molecular analysis.

Two participants declined blood sampling. The remaining 46 individuals underwent the ALEX2 multiplex diagnostic test, an enzyme-linked immunosorbent assay (ELISA)–based platform that simultaneously measures specific immunoglobulin E (sIgE) for 295 allergens. Values ≥0.3 kU/L were considered positive.

Researchers evaluated sensitization to B. germanica-specific allergens and related cross-reactive molecules from Periplaneta americana. B. germanica-specific allergens included Bla g 1, Bla g 2, Bla g 4, Bla g 5, and Bla g 9.

Additional analyses assessed sensitization to a wide range of potential cross-reactive sources, including edible insects, mites, Hymenoptera venom, and seafood.

The researchers first analyzed correlations between SPT results and ALEX2 findings. They then examined molecular sensitization patterns with a focus on cross-reactivity between cockroach allergens and other arthropod, environmental, and seafood allergens.

Cross-reactive proteins drive most allergic responses linked to cockroaches

The study showed that cross-reactivity plays a major role in Polish PAR patients allergic to cockroaches. Only a small proportion displayed elevated IgE responses to cockroach-specific allergens, while most reacted primarily to cross-reactive proteins such as tropomyosins and arginine kinases.

Per a 7 from P. americana strongly correlated with tropomyosins from shrimp, storage mites, and house dust mites, highlighting the role of cross-reactive proteins in complex allergic responses.

The researchers also detected a high correlation between Bla g 5 (glutathione S-transferase) and Der p 11 (paramyosin), reflecting shared structural epitopes across cockroach, mite, and other invertebrate allergens.

Only two patients exhibited IgE sensitization to cockroach-specific allergens, showing elevated IgE levels to Bla g 1 and Bla g 4. Most individuals were sensitized mainly to cross-reactive allergens.

Some patients reacted to arthropod extracts despite lacking detectable IgE to tested cockroach-specific or cross-reactive molecular allergens. This suggests the presence of additional unidentified cross-reactive allergenic molecules in arthropod extracts.

Sensitization patterns also extended to edible insects such as locusts, crickets, and mealworms, as well as storage mites, dust mites, seafood, and wasp species. Profiles varied depending on cockroach species.

Further analyses revealed moderate correlations between B. germanica and house dust mite allergens. Strong correlations were also observed among dog and cat allergens, as well as among house dust mite allergens.

Species-specific differences were evident. Per a 7 correlated with edible insects, storage mites, and seafood allergens, while Bla g 9 showed broader associations with dust allergens and wasp species.

These findings indicate that tropomyosin and related proteins drive extensive cross-reactivity among invertebrate allergens, explaining the complex sensitization patterns observed in cockroach-allergic patients.

Molecular diagnostics could improve allergy diagnosis and treatment decisions

The study shows that cockroach sensitization in PAR patients frequently coincides with sensitization to multiple cross-reactive allergens, including edible insects, seafood, storage mites, dust mites, and wasp species.

Importantly, diagnostic testing based solely on cockroach extracts may overestimate true cockroach sensitization because extract-based tests can detect IgE responses to cross-reactive molecules rather than cockroach-specific allergens.

Component-resolved diagnostics can help distinguish genuine sensitization from cross-reactive responses. This approach may support more precise allergen-specific immunotherapy (ASIT) and improve patient management.

The findings have important clinical implications for allergy diagnosis and treatment by helping clinicians identify true sensitization patterns and anticipate cross-reactive triggers.

Future studies should include larger, more diverse populations while accounting for biological, environmental, socioeconomic, and genetic factors to improve understanding of cross-reactivity and optimize management strategies for patients with allergic rhinitis.