Bed bugs are equipped with mouthparts that are ideal for feeding on blood. During feeding the bed bug injects saliva, which contains an anesthetic and an anticoagulant that can prevent the host from feeling the bite. However, some people do experience a painful bite. The saliva also contains proteins that can elicit various responses from the host. Reactions to the bites can occur immediately, several days later, or not at all. It is most commonly quoted that 20% of people will not react to bed bug bites. However, a recent study determined that 11 out of 24 people experienced no reaction to a first bite and that 18 out of 19 people developed a reaction upon subsequent bites. This suggests that hosts can become sensitized after repeated exposure.
Bites are typically located on skin that is exposed while sleeping such as the face, arms, and legs. They may appear in a random formation or in a straight line, and the number of bites usually depends on the severity of the infestation. Cutaneous responses from bed bug bites can vary greatly. Typically, bites present as erythematous and maculopapular skin lesions that are about 2 to 5 mm in diameter. There is often a hemorrhagic crust or vesicle at the center of the lesion. The bites often look very similar to a mosquito or flea bite and are associated with itching and inflammation. The skin lesions last about 2 to 6 weeks and are usually self-limiting. More complex skin reactions may present as local urticaria and bullous rashes. Scratching the skin lesions can lead to secondary infections and ulcerations.
Although uncommon, systemic reactions from bed bug bites have been reported. These reactions include generalized urticaria, asthma, and, in very rare cases, anaphylaxis. The blood loss a host experiences during a bite typically does not adversely affect the host. However, there have been rare reports of iron deficiency anemia with severe infestations. Mental health issues such as anxiety and insomnia have also been reported in people living in bed bug–infested homes.
US Pharmacist. 2012;37(8):47-50. © 2012 Jobson Publishing