Definition

Pediculosis corporis, often known as body lice, is a skin disease resulting from the infestation of Pediculus humanus corporis, a species of lice that feed on human blood. There exist distinct variations between body lice, specifically Pediculus humanus capitis, which infests the scalp, and Phtirus pubis, which infests the pubic area. Hence, the method of infection and associated risk factors for body lice differ from those of scalp lice and pubic lice.

Causes

Body lice is caused by a type of lice known as Pediculus humanus corporis, as previously stated. Lice are tiny arthropods, comparable in dimensions to sesame seeds. They inhabit clothes and bed sheets, periodically emerging throughout the day to feed on human blood. The neck, shoulders, armpits, waist, and groin are the most often infested body areas by lice. Lice also predominantly infest parts of the body that are covered in clothing.

Eggs laid by lice could also be found on clothing. Lice can be transmitted to your body through direct contact with individuals that have body lice, or by the usage of clothing or bedding that serves as a habitat for lice. Lice possess the ability to move around, yet lack the capacity for flight or jumping. Thus, the transmission of lice is primarily facilitated through human-to-human contact or the use of shared sheets, towels, and clothing.

Lice experience metamorphosis, a life cycle characterized by the transition from eggs/nits to nymphs and ultimately to adults. Adult lice possess six legs, appear brown or grayish-white. They measure 2.5-3.5 centimeters in length, lack wings, and have a flat shape. Lice can feed 1-5 times per day for 60 days. When the body lice are detached from the human body, they will die within a week.

Risk factor

Corporal pediculosis is significantly correlated with inadequate personal hygiene practices, lack of access to clean apparel, and densely populated living environments that facilitate frequent direct physical contact. Body lice outbreaks are prevalent in unsanitary places, such as prisons or refugee camps affected by starvation or disasters. This condition is particularly prevalent among the homeless population in large urban areas, primarily because of their limited access to clean clothing and water. Outbreaks of lice-borne diseases can occur worldwide. Body lice cannot be transmitted by animals such as dogs, cats, and other pets, as their sole hosts are humans.

Symptoms

Frequent manifestations of a body lice infestation are generally as follows:

• Severe itchiness 
• Skin rash resulting from an allergic reaction to lice bites
• Red bumps appear on the skin
• If the lice have been present in the body for an extended period, the skin may become thicker or darker, typically in the waist or groin area.

Additional symptoms could involve swollen cervical lymph nodes and conjunctivitis, characterized by red eyes.

Diagnosis

Pediculosis corporis can be diagnosed through physical examination and the evaluation of patients' symptoms. During the examination, the doctor may detect the presence of crawling lice on your skin. Furthermore, the clothing could also be examined to find the presence of eggs or nits. Lice has sizes comparable to sesame seed, making them visible to the normal human eye. The use a magnifying lens however could facilitate the detection of lice. Nits are commonly observed within the seams of clothing. Other findings that could help in diagnosing this condition may encompass the presence of blood spots on clothing and lick feces.

To differentiate between head lice and body lice, PCR (Polymerase Chain Reaction) test can also be taken. Nevertheless, this test is mostly used for research purposes, rather than for routine diagnostic purposes.

Management

Medication is typically not essential for the treatment of body lice. This condition is normally managed by improving personal hygiene, such as taking a regular bath and washing your clothes with water at a minimum temperature of 50 degrees Celsius. All bedding, clothing, and towels must be washed with hot water and dried either below direct sunlight or using a hot machine.

Itching can be effectively managed by antipruritic medicines, including chlorpheniramine maleate (CTM) or other antihistamines, along with topical steroids. In some circumstances, such as when you have scabies, head lice or pubic lice, your physician could prescribe you with pediculicides, or lice repellents. Typically, a 5% permethrin cream is used and applied all over the body for 8 to 10 hours. Hence, it is advisable to apply permethrin at night when you are going to bed. If you live with family members or other individuals in the same space, the treatment must be given to them as well, even if they do not exhibit any symptoms.

Other therapies comprise of 5% benzyl alcohol lotion, 0.5% ivermectin lotion, a 0.5% malathion lotion, and 0.9% spinosad topical suspension. It is important to exercise caution when using these medications, elevated concentrations could be toxic to people. It is advisable to thoroughly review the medication's usage instructions before using it.

Complications

Complications are rarely observed in cases of body lice. Nevertheless, potential complications that may arise include:

• Secondary infection. When the lick penetrates your skin to consume blood, it has the potential to cause skin irritation. Scratching the lick bite marks might also lead to irritation. In this case, the irritated skin could be infected, for example by bacteria.
• Skin alterations. Prolonged infestation of body lice can lead to alterations of the skin, characterized by increased skin thickness and hyperpigmentation, particularly in areas such as the waist, groin, and upper thighs.
• Disease spread. Body lice are capable of carrying and spreading a range of bacterial infections, including typhoid fever (caused by Rickettsia), relapsing fever, and Bartonella infection (often known as trench fever). The presence of other bacteria on body lice includes Salmonella typhi, which is responsible for causing typhoid fever, as well as Serratia marcescens and Acinetobacter baumannii. These infections have the potential to cause severe sickness, even death, and the occurrence of epidemics. These outbreaks commonly manifest in regions that experience armed conflict, natural calamities, high poverty rates, or challenging environmental conditions that hinder the maintenance of personal hygiene (such as severe droughts resulting in limited access to clean water). 

The transmission of these illnesses occurs through the feces of infected lice. When the lice feed on human blood, the lick typically dispose of their feces onto the skin, which might then enter the bite marks, eyes, or mouth through scratching. Nevertheless, Bartonella infections could arise when an individual presses the lick and subsequently places their palms to the mouth or rubs their eyes.

Prevention

Pediculosis corporis primarily impacts individuals who experience difficulty in taking a bath or changing clothes regularly. To prevent this, it is advisable to maintain personal hygiene and ensure that you change your clothes at least once a day. Sharing clothes, bedding, or towels with someone who has body lice is strongly discouraged. In the instance that lice are detected, it is recommended to wash the clothes using a washing machine and hot water, followed by drying them in the sun. It is important that all family members that live with you also receive treatments, even if they do not show any symptoms.

When to see a doctor?

If body lice persist despite efforts to improve hygiene or if a skin infection occurs as a result of scratching the lice bites, it is advisable to seek medical attention. These infections are often distinguished by the presence of pus-filled blisters or pus discharge on the skin. Typically, this condition is resolved by improving hygiene without complications.

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