Continuing Education Activity

Join us for an engaging continuing medical education (CME) session on pediculosis corporis, a skin condition caused by body lice (Pediculus humanus corporis) that feed on human blood. Unlike head and pubic lice, body lice exhibit unique behaviors involving residing in the seams of clothing and bedding and only moving to human skin for feeding. This session will delve into the distinctive characteristics of body lice, exploring their parasitic nature and the crucial differences between body and head lice. Notably, body lice can transmit severe bacterial diseases such as trench fever, relapsing fever, and epidemic typhus to humans, making their identification and management vital in preventing associated morbidity and mortality.

Our expert speakers will guide attendees through the evaluation and treatment of pediculosis corporis, emphasizing the role of the interprofessional healthcare team in delivering optimal care. Attendees will gain insights into the importance of early recognition and appropriate antibiotic therapy to reduce the morbidity and mortality associated with louse-borne diseases. Additionally, the session will highlight effective patient education strategies, focusing on providing patients with the necessary guidance for eradication through regular access to hygiene facilities and laundered clothing. Stay updated on the latest developments in managing pediculosis corporis and enhance your skills to improve patient outcomes.

Objectives:

• Identify the etiology of pediculosis corporis.
• Determine the role of poor hygiene, unclean clothing, and living in unsanitary conditions in the spread of body lice in pediculosis corporis.
•  Assess the management considerations for patients affected by pediculosis corporis.
• Implement effective collaboration and communication among interprofessional team members to improve outcomes and treatment efficacy for patients affected by pediculosis corporis.

Introduction

Pediculosis corporis is a skin condition caused by body lice (Pediculus humanus corporis) that feed on human blood. Body lice are parasitic insects that feed on human blood. The 3 types of lice that feed on humans are the head louse (Pediculus humanus capitis), the pubic or crab louse (Pthirus pubis), and the body louse. There has been debate amongst entomologists regarding the proper taxonomy of head and body lice; some identify them as two different species, while others group them as a single species. Those considering them as two distinct species identify body lice as Pediculus humanus, while those who see them as one species identify them as Pediculus humanus humanus. In the medical literature, body lice are often referred to as Pediculus humanus corporis, but according to the rules of the International Commission on Zoological Nomenclature, this is an improper designation.[1]

Studies have identified that the head and body lice are closely related, with genetic studies demonstrating that body lice possess only one gene that is not also present in head lice.[2] 

Unlike head and pubic lice, body lice do not live on the skin but rather live and lay their eggs in stitchings of clothing or bedding, moving to the skin only to feed. The most significant difference between body and head lice is the distinct ability of body lice to transmit the bacterial diseases of trench fever, relapsing fever, and epidemic typhus to humans.[2]

Etiology

Body lice are ectoparasites that must feed on human blood to survive and have a global distribution. They assume 3 forms across their life cycle, starting with the egg or nit, progressing to the nymph, and finally, the adult stage. As with head lice, nits are oval and appear yellow or white. However, body lice attach their eggs to the proximal hair shafts, unlike head lice, which lay their eggs in clothing seams. A nymph is an immature louse, which, except for its smaller size, has the same appearance as an adult louse. Adult lice have 6 legs, are tan to grayish-white in color and 2.5 to 3.5 cm in length, have no wings, and are flat in shape (see Image. Body Lice).

Body lice feed 1 to 5 times daily and can live up to 60 days. Body lice will die within a week after being separated from a human host. Recently, it has been established that severe iron deficiency anemia is linked with the development of pediculosis corporis.[3]

Epidemiology

As body lice cannot jump or fly, they spread primarily by direct contact, though transmission can also occur through clothing, bed linens, and towels. Infestations are strongly correlated with poor body hygiene, lack of access to clean clothing, and crowded conditions, facilitating lice spread through direct physical contact. Outbreaks most commonly occur in situations where large groups of people live in unsanitary conditions such as prisons or camps of large groups of refugees from war, famine, or natural disasters. In the United States and other developed countries, body lice infestations most commonly occur in homeless populations because of the lack of access to clean clothes or showers. Outbreaks of body lice infestations and louse-borne diseases continue to occur globally and have been documented in jails and refugee camps in central and eastern Africa, rural areas in the Peruvian Andes, and amongst rural populations in Russia.[2][4][5]

Pathophysiology

Body lice infestations can involve thousands of mites, each biting an average of 5 times daily. During feeding, body lice pierce the skin, inject a salivary anticoagulant, and then suck the blood meal into their digestive tract. Bites of the body louse can produce a variety of skin lesions, and severe pruritus is thought to be due to an allergic or inflammatory reaction to the louse's saliva.[6] Intense scratching of pruritic bites can result in skin excoriation, potentially leading to significant secondary bacterial infections.

The most significant medical impact of body lice is their ability to transmit bacterial diseases, most notably trench fever caused by Bartonella quintana, relapsing fever caused by Borrelia recurrentis, and epidemic (louse-borne) typhus caused by Rickettsia prowazekii.[7] Trench fever and epidemic typhus are transmitted not by louse bites but through infected feces. When feeding, the body louse often excretes feces onto the skin, which can be inadvertently rubbed into the bite site, eyes, or mucous membranes. Rickettsia prowazekii can also be transmitted through inhalation of aerosolized fecal dust, which has been documented as a potential source of infection for clinicians. Unlike trench fever and epidemic typhus, the transmission of relapsing fever, caused by Borrelia recurrentis, does not occur through contaminated feces. Infection occurs when a person crushes an infected louse, and the bacteria invade the bite site or the skin of the fingers or hand that crushed the louse.[7] In addition, a person can acquire the infection if they rub their eye or put their fingers in their mouth after crushing the louse.

Additional pathogenic bacteria in body lice include Salmonella typhi, Serratia marcescens, and Acinetobacter baumannii. The DNA of Yersinia pestis, which causes bubonic plague, has been identified in body lice, and it is believed they may serve as supplementary vectors for the organism.[1]

History and Physical

Historical clues such as poor body hygiene, lack of access to clean clothing, homelessness, and residing in crowded, unsanitary conditions should prompt consideration for body louse infestation and louse-borne infections. The primary symptom of body lice infestations is severe pruritus.

The dermatologic findings in body lice infestation vary but include pyoderma, erythematous macules, wheals, and hemorrhagic puncta. The severe pruritus of bites can cause intense scratching, leading to excoriations and secondary infections.[8] In chronic body lice infestation, frequently bitten areas of the skin can develop notable thickening and discoloration, a condition known as “vagabond’s disease.”[9] Dermatologic findings tend to be most prominent in areas where clothing seams are in contact with the skin, such as the waist, groin, thighs, and axillary folds.[6] Additional physical exam findings including cervical lymphadenopathy and conjunctivitis, are often present.

Unlike head and pubic lice, infestation with body lice is typically diagnosed by finding eggs and lice in seams of clothing rather than on the skin.[2] Therefore, an important exam component in patients suspected of having body lice includes careful inspection of their clothing. In addition to lice, indirect findings such as blood stains or louse feces may be discovered.[10]

Evaluation

While body lice may occasionally be found crawling on the patient’s skin, an infestation is typically diagnosed by finding eggs and lice in clothing seams. A PCR assay has been developed to differentiate between head and body lice but is primarily used for research purposes rather than to support clinical decision-making.

Treatment / Management

Treatment of body lice does not usually require the use of a pediculicide because improvements in hygiene, including showering and laundering clothing in hot water at least 50 °C, will most often eradicate the infestation.[2] All clothing, bed linens, and towels should be washed in hot water and machine-dried on the hot cycle.

Itching can be treated with topical corticosteroids and systemic antihistamines. Secondary skin infections are managed with appropriate systemic antibiotics. While pediculicides are not required to eradicate body lice infections, they are often used if body lice or nits are found on body hair or if there is a co-infection with head lice, pubic lice, or scabies.[6] In these cases, pharmacologic treatment employs the same agents for pubic and head lice, most commonly permethrin cream applied to the entire body for 8 to 10 hours. Additional treatments include 5% benzyl alcohol lotion, 0.5% ivermectin lotion, 0.5% malathion lotion, 0.9% spinosad topical suspension, and 1% lindane shampoo.[2][11] 

Lindane is not recommended for first-line treatment due to some potentially serious reactions including neurotoxicity and seizures. In some settings, such as refugee camps with large numbers of people, environmental application of chemical insecticides may be needed to prevent the spread of body lice and louse-borne infections.[12][13][14]

Differential Diagnosis

The differential diagnosis of dermatologic findings in body lice infestation includes scabies, contact dermatitis, atopic dermatitis, drug reaction, and viral exanthem. Co-infection with head lice, pubic lice, scabies, and fleas may be found, especially in refugee populations.[6]

A high index of suspicion should be maintained for trench fever, relapsing fever, and epidemic typhus in patients with body lice infestation presenting with signs or symptoms of systemic infections. Other infectious diseases with similar manifestations include babesiosis, brucellosis, Q fever, typhoid fever, leptospirosis, ehrlichiosis, and tularemia.

Prognosis

The prognosis for eradicating body lice infestation is excellent if patients shower regularly and have weekly access to laundered clothing and bedding. Significant morbidity and mortality are associated with louse-borne diseases but can be reduced substantially with early recognition and appropriate antibiotic therapy.

Epidemic typhus can cause vasculitis, leading to limb ischemia, gangrene, central nervous system (CNS) dysfunction, and multiorgan failure. Mortality ranges from 20% to 40% in untreated patients but decreases to 3% to 4% with appropriate antibiotic therapy.

Louse-borne, relapsing fever mortality rate is approximately 40% if untreated, while the mortality rate with treatment drops to around 4%.

Trench fever, caused by B. quintana, tends to be self-limited in immunocompetent people but can result in the development of endocarditis, which can lead to increased morbidity and mortality.

Complications

While body lice infestation does not usually lead to severe complications, there can be associated issues and secondary problems. Here are some potential complications of pediculosis corporis:

• Secondary Bacterial Infections: Constant scratching of the affected areas can lead to breaks in the skin, creating entry points for bacteria. This may result in secondary bacterial infections, such as impetigo or cellulitis. These infections can cause redness, swelling, and pus-filled lesions on the skin.
• Prurigo Nodularis: Chronic scratching can lead to the development of prurigo nodularis, a skin condition characterized by itchy nodules or papules. These nodules can be persistent and may require medical attention.
• Excoriations and Dermatitis: Scratching due to itching can cause excoriations (superficial wounds) and dermatitis. Persistent scratching can exacerbate inflammation and lead to more significant skin problems.
• Psychological Distress: Chronic infestations and the associated itching can cause significant psychological distress, leading to stress, anxiety, or depression in affected individuals. Social stigma and embarrassment may further contribute to psychological complications.
• Complications in Vulnerable Populations: Individuals who are already vulnerable, such as those with weakened immune systems, older adults, or those living in crowded or unsanitary conditions, may be more prone to complications. In such cases, the impact of body lice infestation can be more severe.
• Transmission of Pathogens: While body lice do not transmit diseases directly, their presence can indirectly contribute to transmitting specific bacterial pathogens. Body lice have been associated with transmitting diseases like trench fever, typhus, and relapsing fever. These diseases are more likely in conditions of poor hygiene and overcrowding.
• Anemia: In extreme cases of long-term and severe body lice infestation, blood loss due to repeated lice feedings could lead to anemia. However, this is a rare complication.

Deterrence and Patient Education

Infestations are strongly correlated with poor body hygiene, lack of access to clean clothing, and crowded conditions. They most commonly occur in situations where large groups of people live in unsanitary conditions, such as prisons or camps of large groups of refugees from war, famine, or natural disasters. Therefore, maintaining personal hygiene and avoiding sharing clothes or personal amenities is recommended. 

Pearls and Other Issues

• Unlike head and pubic lice, body lice do not live on the skin but rather live and lay their eggs in seams of clothing or bedding, moving to the skin only to feed.
• The most significant difference between body and head lice is that body lice transmit the bacterial diseases trench fever, relapsing fever, and epidemic typhus to humans.
• Infestations are strongly correlated with poor body hygiene, lack of access to clean clothing, and crowded conditions. They most commonly occur in situations where large groups of people live in unsanitary conditions, such as prisons or camps of large groups of refugees from war, famine, or natural disasters.
• In the United States and other developed countries, body lice infestations most commonly occur in homeless populations who lack access to clean clothes or showers.
• Bites of the body louse can produce a variety of skin lesions and severe pruritus, which is thought to be due to an allergic or inflammatory reaction to the louse's saliva.
• Infestation with body lice is typically diagnosed by finding eggs and lice in seams of clothing rather than on the skin.
• Treatment of body lice does not usually require the use of a pediculicide because improvements in hygiene, including showering and laundering clothing in hot water, will usually eradicate the infestation.[15][16]

Enhancing Healthcare Team Outcomes

Body lice are often encountered by nurse practitioners, primary care providers, internists, emergency department physicians, and pharmacists. Improving healthcare practitioners' understanding of risk factors, transmission, clinical manifestations, and management of pediculosis corporis, emphasizing educating patients on the importance of personal hygiene and laundering clothes in hot water, will ensure timely treatment and prevent further transmission of body lice.

Symptoms like pruritus are managed with antihistamines and topical corticosteroids.

While pediculicides are not required to eradicate body lice infections, they are often used if body lice or nits are found on body hair or if there is a co-infection with head lice, pubic lice, or scabies.[6] 

The most significant difference between body and head lice is the distinct ability of body lice to transmit the bacterial diseases trench fever, relapsing fever, and epidemic typhus to humans.

The outcomes for patients who remain compliant with good body hygiene are good.

Review Questions

• Access free multiple choice questions on this topic.
• Comment on this article.

References

1.

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2.

Sangaré AK, Doumbo OK, Raoult D. Management and Treatment of Human Lice. Biomed Res Int. 2016;2016:8962685. [PMC free article: PMC4978820] [PubMed: 27529073]

3.

Woodruff CM, Chang AY. More than skin deep: Severe iron deficiency anemia and eosinophilia associated with pediculosis capitis and corporis infestation. JAAD Case Rep. 2019 May;5(5):444-447. [PMC free article: PMC6510936] [PubMed: 31193000]

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Newton PN, Fournier PE, Tappe D, Richards AL. Renewed Risk for Epidemic Typhus Related to War and Massive Population Displacement, Ukraine. Emerg Infect Dis. 2022 Oct;28(10):2125-2126. [PMC free article: PMC9514335] [PubMed: 36007931]

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Dave MD, Mehta HH, Gorasiya AR, Nimbark DN. Pediculosis pubis presenting as pediculosis capitis, pediculosis corporis, and pediculosis ciliaris in a case of Alport syndrome. Indian J Sex Transm Dis AIDS. 2023 Jan-Jun;44(1):71-73. [PMC free article: PMC10343108] [PubMed: 37457509]

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Whitfield A. Case of Vagabond's Disease. Proc R Soc Med. 1926;19(Dermatol Sect):31. [PMC free article: PMC1948743] [PubMed: 19984910]

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Nyers ES, Elston DM. What's eating you? human body lice (Pediculus humanus corporis). Cutis. 2020 Mar;105(3):118-120. [PubMed: 32352435]

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Young C, Argáez C. Ivermectin for Parasitic Skin Infections of Lice: A Review of Comparative Clinical Effectiveness, Cost-Effectiveness, and Guidelines [Internet]. Canadian Agency for Drugs and Technologies in Health; Ottawa (ON): May 14, 2019. [PubMed: 31487135]

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Dadabhoy I, Butts JF. Parasitic Skin Infections for Primary Care Physicians. Prim Care. 2015 Dec;42(4):661-75. [PubMed: 26612378]

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El-Bahnasawy MM, Abdel FE, Morsy TA. Human pediculosis: a critical health problem and what about nursing policy? J Egypt Soc Parasitol. 2012 Dec;42(3):541-62. [PubMed: 23469630]

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Feldmeier H, Heukelbach J. Epidermal parasitic skin diseases: a neglected category of poverty-associated plagues. Bull World Health Organ. 2009 Feb;87(2):152-9. [PMC free article: PMC2636197] [PubMed: 19274368]

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Disclosure: Jim Powers declares no relevant financial relationships with ineligible companies.

Disclosure: Talel Badri declares no relevant financial relationships with ineligible companies.

Disclosure: Hasnain Syed declares no relevant financial relationships with ineligible companies.