Anaphylaxis—Although the bites of Triatoma and A cristatus present differently, both can cause anaphylaxis. Triatoma is implicated more often than A cristatus as the cause of anaphylaxis.12 In fact, Triatoma bites are among the more common causes of anaphylaxis from bug bites, with multiple cases of these reactions reported in the literature.12,13
Symptoms of Triatoma anaphylaxis include acute-onset urticarial rash, flushing, dyspnea, wheezing, nausea, vomiting, and localized edema.2 The cause of anaphylaxis is proteins in Triatoma saliva, including 20-kDa procalin, which incites the systemic reaction. Other potential causes of anaphylaxis include serine protease, which has similarities to salivary protein and desmoglein in humans.11
The degree of reaction to a bite depends on the patient's sensitization to antigenic proteins in each insect’s saliva.4,6 Patients who have a bite from a triatomine bug are at risk for subsequent bites, as household infestation is likely due to the pliability of the insect, allowing it to hide in small spaces unnoticed.8 In the case of a bite from Triatoma or A cristatus, sensitization may lead to severe and worsening reactions with subsequent bites, which ultimately can result in life-threatening anaphylaxis.1,6
Treatment and Prevention
Treatment of Triatoma and A cristatus bites depends on the severity of the patient’s reaction to the bite. A local reaction to a bite from either insect can be treated supportively with local corticosteroids and antihistamines.3 If the patient is sensitized to proteins associated with a bite, standard anaphylaxis treatment such as epinephrine and intravenous antihistamines may be indicated.14 Secondary infection can be treated with antibiotics; a formed abscess might need to be drained or debrided.15
There’s No Place Like Home—Because Triatoma bugs have a pliable exoskeleton and can squeeze into small spaces, they commonly infest dwellings where they find multiple attractants: light, heat, carbon dioxide, and lactic acid.8 The more household occupants (including pets), the higher the levels of carbon dioxide and lactic acid, thus the greater the attraction. Infestation of a home can lead to the spread of diseases harbored by Triatoma, including Chagas disease, which is caused by the parasite Trypanosoma cruzi.5
Preventive measures can be taken to reduce the risk and extent of home infestation by Triatoma bugs, including insecticides, a solid foundation, window screens, air conditioning, sealing of cracks and crevices, outdoor light management, and removal of clutter throughout the house.8 Because Triatoma bugs cannot bite through clothing, protective clothing and bug repellent on exposed skin can be employed. Another degree of protection is offered by pest management, especially control of rodents by removing food, water, and nests in areas where triatomine bugs feed off of that population.8,14
Unlike triatomine bugs, wheel bugs tend not to invade houses; therefore, these preventive measures are unnecessary. If a wheel bug is identified, do not engage the arthropod due to the defensive nature of its attack.4,9 Such deliberate avoidance should ensure protection from the wheel bug’s painful bite.