Healthy teen awakens with lesions in early morning hours
What's your diagnosis?
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A healthy, adolescent boy is seen for recurrently awakening with pruritic, urticarial-like lesions between his upper thighs extending to his mid-thorax.
Figure 1. Urticarial lesions on a teenage patient’s thorax. Image: James H. Brien, DO.Some lesions appear to be in a linear pattern, while some others are in clusters or discrete solitary lesions (Figures 1 and 2). The cause of these lesions usually awakens him in the early morning hours, about 10 times over the last 2 months. A search for any insects in his room failed to discover a cause. There is a family dog, but it does not sleep or spend significant time in the patient’s room. The patient does not have a history of allergies or pre-existing skin problems, and no other family member, including a brother and both parents, have experienced any similar problem.
Figure 2. Lesions on the patient’s thighs. Image: James H. Brien, DO.What’s your diagnosis?
A. Bed bugs
B. Dust mites
C. Fleas
D. Kissing bugs
Answer and discussion:
The best answer is the bed bug — Cimex lectularius or C. hemipterus (Figure 3). It goes through several stages of development, requiring a blood meal before each stage. They tend to seek their “blood donor” at night as they sleep, then return to a nest usually out of sight. They can be difficult to find because they can hide out in any space, crack or crevice they can find, such as between mattresses, the bed frame, breaks in the wallpaper near the bed, etc. Their blood meals may be separated by days to weeks; therefore, there may be nights without any bites. However, depending on the number of bugs, bites may occur every night. It may take a professional exterminator to discover the nest and almost always requires killing or removing them. Since they do not carry any disease, they are only a nuisance, which may rise psychologically to the level of a disease.
Figure 3. Cimex lectularius (bed bug).Image: CDC/CDC-DPDx; Blaine Mathison.Dust mites do not bite but may cause allergic symptoms to those who are sensitized. Fleas can also bite at night (or any other time) and may cause a papular urticarial reaction like a bed bug. However, they are not hard to find and eradicate. Usually, there is an indoor/outdoor dog or cat in the home.
The kissing bug, or triatomine (Figure 4) also tends to bite only at night, but they prefer the capillary-rich area about the face — thus the name, kissing bug. Unlike the harmless bed bug, about 50% of kissing bugs may transmit the organism responsible for Chagas disease, named for Dr. Carlos Chagas, who first described the disease in Brazil in 1909. Since then, Chagas disease has been found from South America all the way to the southern half of the United States, mostly in areas of poor housing and sanitation. Chagas disease (American trypanosomiasis) is caused by the parasite Trypanosoma cruzi, which can be a silent infection or consist of symptoms of common viral infections in the acute phase and may last several months before transitioning into the chronic phase. The chronic phase may be lifelong if not treated, resulting in the most dangerous complication, Chagas cardiomyopathy, accompanied by a potentially life-threatening conduction defect that about one-third of those infected will develop if untreated. About 10% of those infected will have gastrointestinal motility problems. Recommended drugs include benznidazole and nifurtimox (see Nelson’s Pediatric Antimicrobial Therapy, 27th edition, page 214). The best quick resource is the CDC’s website.
Figure 4. Triatomine (kissing bug). Image: CDC.Columnist comments:
I want to thank one of my old pediatric residents, Jay Capra, MD, who has contributed to this column in the past. I also want to thank the patient who donated his pictures, Michael Beckham, MD, who is also Dr. Capra’s nephew and now a practicing internist.
As most providers in the practice of medicine know, there are times when proof of the cause of a complaint or condition is not confirmed, but a reasonable conclusion can be reached by deductive reasoning or determined retrospectively based on a response to management or the passage of time without new information. In this case, the bugs were never seen, but extermination efforts were undertaken with resolution. The skin condition has never returned.
References:
Bradley JS, Nelson JD, eds. Nelson’s Pediatric Antimicrobial Therapy 2021. 27th ed. American Academy of Pediatrics; 2021:214.
CDC. Parasites – American trypanosomiasis (also known as chagas disease). https://www.cdc.gov/parasites/chagas/index.html. Last reviewed Aug. 24, 2023. Accessed Feb. 12, 2024.
Nunes MCP, et al. Circulation. 2018;doi:10.1161/CIR.0000000000000599.
Tustin AW, Bowman NM. Pediatr Rev. 2016;doi:10.1542/pir.2015-0116.