Re: Bed bug infestation
Bernadeschi et al.1 have reviewed a selection of developments into the clinical significance of bed bugs, subsequent to the review by Goddard & deShazo2. For several reasons, it is unfortunate that the authors do not follow the evidence-based conclusions by the latter.
First, finding bed bugs near a patient is weak evidence that they caused systemic responses or bite symptoms: other parasites causing similar symptoms may have gone undetected.
Second, several other reported symptoms of bed bug bites are also unsupported by evidence but may affect clinical interpretation. Although it is unfortunate to state, the truth is that no data exist that allow clinicians to distinguish bites by bed bugs from those of other ectoparasites (fleas or mosquitoes), and certainly not the guidelines provided by Bernadeschi et al. in their table. For example, there is no evidence that bed bug bites are arranged linearly in triplets (the cited "breakfast-lunch-dinner pattern") in general3, or in comparison with other arthropod bites. It has been recognised in the early last century that this pattern very likely arises from the fact that several bed bug individuals will bite body parts that are not covered by the edge of the beddings (hence the linear arrangement). The anecdotal evidence I can provide from the cited study on controlled bites4 is having experienced tens of thousands of bites: when skin space is not restricted, linear patterns do not arise (see also the figures in refs3,4). The number of bites or bite attempts per individual bed bug can vary from one to several. If there are three bites, they are almost inevitably arranged in some kind of row.
Third, there is no evidence at all that pruritus from bed bug bites is more intense in the morning than at other times of day. Unless such evidence is available I recommend that clinicians and health workers do not use it as a diagnostic feature.
Fourth, suggesting that "travelling" is the context in which bedbug bites should be diagnosed is an unsupported belief. This could lead clinicians and public health workers to diagnose bed bug bites presented by patients returning from travelling and so generate a vicious circle in that every bite after travelling increasingly are assigned to bed bugs.
Fifth, the suggestions on patient education may be helpful but lack an evidence base (except for the suggestion to wash cloths at > 60°C which had been tested5). That 10% of the people in England recognised bed bugs on pictures is erroneous, the number referred to people recognising a real bed bug6. Recognising bed bugs from pictures in the media is less effective than other sources of information7.
Sixth, there is no evidence that treating bites with topical steroids is more effective than doing nothing2.
Bed bugs seem to attract urban myths as ineradicable as the bed bug itself. Repeating them may increase the general awareness of bed bugs but does not necessarily lead to better treatment. Consulting Goddard & deShazo2 as well as Doggett et al.7 seems to provide the safer option with fewer opinion and more evidence.
1. Bernadeschi et al. Bed bug infestation. BMJ 2013, 356:f138, doi: http://dx.doi.org/10.1136/bmj.f138
2. Goddard J, deShazo R. Bed bugs (Cimex lectularius) and clinical consequences of the their bites. JAMA 2009; 301:1358-1366.
3. Doggett SL et al. Bed bugs: Clinical relevance and control options. Ciln Microbiol Rev 2012, 25:164-192, doi: 10.1128/CMR.05015-11
4. Reinhardt K et al. Sensitivity to bites by the bedbug, Cimex lectularius. Med Vet Entomol 2009, 23:163-166
5. Naylor RA, Boase CJ Practical solutions for treating laundry infested with Cimex lectuiarius (Hemiptera: Cimicidae). J Econ Entomol 2010, 103:136-139
6. Reinhardt K et al. Who knows the bed bug? Knowledge of adult bed bug appearance increases with people’s age in three counties of Great Britain. J Med Entomol 2008, 45: 956-958
7. Seidel C, Reinhardt K Bugging forecast: unknown, disliked, occasionally intimate. Bed bugs in Germany meet unprepared people. PLOS One 2013, 8e51083, doi:10.1371/journal.pone.0051083
Dr Klaus Reinhardt
Department of Animal and Plant Sciences
University of Sheffield
Sheffield S10 2TN
University of Tuebingen
Animal Evolutionary Ecology
Auf der Morgenstelle 28
Competing interests: No competing interests