Pediatric Annals

Special Issue Article 

Infestations, Bites, and Insect Repellents

Sonia Kamath, MD; Brandi Kenner-Bell, MD

Abstract

Infestations and arthropod bite reactions in children are common reasons for presentation to pediatric health care providers. Infestations in children include head lice, scabies, and other mites. Fleas and bed bugs are common causes of bite reactions in children, and papular urticaria is a chronic, recurrent eruption resulting from delayed hypersensitivity to a variety of insect bites. Both infestations and bite reactions may result in severe pruritus with associated sleep disturbance and can be a source of significant distress for patients and families. In this review, we discuss infestations and bite reactions affecting pediatric patients, along with the approach to treatment and prevention of these conditions. [Pediatr Ann. 2020;49(3):e124–e131.]

Abstract

Infestations and arthropod bite reactions in children are common reasons for presentation to pediatric health care providers. Infestations in children include head lice, scabies, and other mites. Fleas and bed bugs are common causes of bite reactions in children, and papular urticaria is a chronic, recurrent eruption resulting from delayed hypersensitivity to a variety of insect bites. Both infestations and bite reactions may result in severe pruritus with associated sleep disturbance and can be a source of significant distress for patients and families. In this review, we discuss infestations and bite reactions affecting pediatric patients, along with the approach to treatment and prevention of these conditions. [Pediatr Ann. 2020;49(3):e124–e131.]

Infestations and arthropod bite reactions are common reasons for children to present to pediatricians, urgent care, and emergency departments. We review the clinical presentation, management, and prevention of common infestations and bites, including lice, mites, fleas, bed bugs, and papular urticaria.

Lice

Lice are obligate parasitic insects. Three main species affect humans: Pediculis humanus capitis (head louse), Pediculus humanus (body louse), and Pthirus pubis (crab louse).1–3 Human body lice and head lice have a similar appearance, with elongated bodies approximately 2 to 3 mm in length, 3 pairs of legs, and a tan-gray color.1,2 Pubic lice have shorter bodies with a distinctive appearance that is similar to a crab.3 Head lice are the most common type affecting humans, and they tend to affect school-aged children the most.1

Pediculosis capitis (Head Lice)

Head lice are spread through direct head-to-head contact. They are unable to hop, jump or fly.1 Transmission via fomites such as brushes, combs, and towels may occur but is less likely because lice usually do not survive longer than one day off the scalp.1 Although the infestation can cause significant psychosocial distress, reassurance can be provided that Pediculus humanus capitus is not a vector for any infections and is not a sign of poor hygiene.1

Head lice feed on blood by injecting their saliva into the scalp, and pruritus occurs from sensitization to saliva. With an initial infestation, patients may be asymptomatic for 4 to 6 weeks as sensitivity develops.1 Secondary excoriations may be present on the scalp and posterior neck, and bacterial superinfection may occur. Hypersensitivity reactions to active head lice infestation may manifest as diffuse eczematous dermatitis or diffuse skin-colored papules (“pediculid” reaction).4,5 Cervical and occipital lymphadenopathy may be present. Nits, or empty egg cases, may be confused with scaling from seborrheic dermatitis or hair casts but can be distinguished by their firm adherence to the hair shaft.

The diagnosis of head lice can be made via identification of eggs, nymphs, or adult lice. Nits alone are not diagnostic of active infestation.6 Although nits appear white, viable eggs are the same color as the hair shaft and are most easily identified on the occipital and retroauricular scalp.1,6 Nymphs and adult lice move quickly and avoid light, making visual identification difficult. “Wet combing” (moistening hair with conditioner and then combing) can improve accuracy of diagnosis by slowing down the lice.7

Treatment for head lice should be initiated only after confirmation of an active infestation to avoid unnecessary pediculicide exposure and treatment resistance. First-line therapy remains over-the-counter permethrin 1% lotion, which has been well-studied in humans, has minimal toxicity, and is approved by the US Food and Drug Administration (FDA) for children age 2 months and older. Permethrin has both pediculicidal and ovicidal properties.1 Permethrin should be applied to damp hair, then rinsed out after 10 minutes to limit skin absorption. A repeat treatment 7 to 10 days later is recommended if live lice are seen.1 Permethrin resistance has been reported, although the exact rate remains unclear. Pyrethrins, which are created from natural extracts from chrysanthemums, are another over-the-counter topical treatment;1 however, increasing resistance has been noted.1 For those who do not respond to treatment with over-the-counter medication, clinicians should consider the possibility of misdiagnosis, nonadherence to treatment, re-infestation, or medication resistance. If resistance is suspected, several prescription pediculicides are available (Table 1).

US Food and Drug Administration-Approved Topical Treatments for Head Lice

Table 1.

US Food and Drug Administration-Approved Topical Treatments for Head Lice

A variety of other medications have been used off-label for head lice with variable efficacy, including permethrin 5% cream, crotamiton 10% lotion, oral ivermectin, and trimethroprim-sulfamethoxazole.1 Newer medications under investigation include tocopheryl acetate 20% spray (a vitamin E-based oil that immobilizes lice), and abametapir 0.74% lotion (a metalloproteinase inhibitor essential for louse egg survival.)8,9 Alternative approaches have included various essential oils and desiccation caused by applying hot air to the scalp using an expensive custom-built machine.1

Although there is little evidence to support it, for those who prefer to avoid pediculicides, manual removal of lice, eggs, and nits by wet-combing or using an occlusive agent, such as petrolatum, can be employed if closely monitored and repeated for 3 weekly cycles.1 Even for patients treated with a pediculicidal agent, viable eggs (within 1 cm of the scalp) should be removed manually after treatment.1 Because nits are firmly cemented to the hair shaft, they may persist several months after the infestation has been successfully treated.6 Manual nit removal can help reduce social stigma and confusion about whether a patient has been adequately treated.1 Notably, the American Academy of Pediatrics opposes “no nit” policies in schools, particularly because they lead to unnecessary missed school days, and the presence of nits alone does not accurately predict active infestation.1

Empiric treatment of non-infested close contacts is not recommended, with the exception of those sharing a bed.1 Other household members and close contacts should be treated only if lice are found. Personal belongings that have been in contact with the head of the infested patient within the 24 to 48 hours prior to treatment should be cleaned in hot water.1

Pediculosis corporis (Body Lice)

Body lice are more prevalent in adults.6 The human body louse is a vector for multiple diseases, including trench fever, louse-borne relapsing fever, and epidemic typhus.2,6 Infestations with body lice are spread through direct contact and tend to affect people in crowded living conditions.2,6 Body lice may survive for 5 to 7 days away from a human host and may spread through contact with contaminated clothing or linens.2 Patients display severe pruritus, particularly at nighttime. Clinical examination reveals bite reactions, excoriations, and lichenified plaques from chronic scratching. Body lice may be found on body hair; however, more often lice and eggs are found in clothing seams, particularly the waistband.6 Treatment consists of improving hygiene through bathing and laundering clothing and linens in hot water. Patients with extensive body hair may require treatment with a topical pediculicide. Pyrethrin with piperonyl butoxide is the only pediculicide approved by the FDA for this purpose; however; permethrin 5% cream may also be used.2,6

Pediculosis pubis (Pubic Lice)

Pubic lice are considered a sexually transmitted infestation and are much more common in adults. Although nonsexual transmission may occur, pubic lice in children should raise suspicion for possible sexual abuse.3 Patients should undergo screening for concurrent sexually transmitted infections.6 One study showed that adolescents with pubic lice infestations were twice as likely to have gonorrhea or chlamydia compared to non-infested teens.10

As with other lice infestations, pruritus is often the presenting symptom. Clinical examination reveals lice and nits attached to pubic hair and adjacent body hair. Occasionally, pubic lice may also be present on the scalp, eyebrows, or eyelashes.6 Blue-gray macules on the lower abdomen and thighs, known as maculae cerulae, are a classic finding, resulting from dermal hemosiderin deposition from bites.6

Treatment consists of the same topical pediculicides used for head lice. In addition, permethrin 5% cream is often used.6 For eyelash involvement, topical pediculicides should be avoided. Instead, ophthalmic petrolatum ointment 2 to 4 times daily for 10 days is recommended.3 All sexual contacts should be examined and treated if an active infestation is identified. Clothing and bedding should be washed and dried in hot cycles.

Mites

Scabies

Scabies is an infestation caused by the Sarcoptes scabiei var hominis mite.11 It is much more common in infants and children compared to adults, and those in crowded living conditions are at higher risk.11 Scabies is transmitted through close contact, and the mites may survive on fomites for several days, depending on the environment.

Scabies mites burrow into the top layer of the epidermis within 30 minutes of contact. Because the symptoms associated with scabies are caused by delayed type IV hypersensitivity, patients often remain asymptomatic for up to 6 weeks after initial exposure.11

The two main clinical presentations of scabies include classic and crusted scabies. Whereas classic scabies results from infestation with only 10 to 12 mites, crusted scabies is a more severe variant resulting from uncontrolled proliferation of several thousand mites.

Classic scabies presents with severe pruritus and sleep disturbance. There are often other family members with itch.12 Skin lesions vary in morphology. Burrows, which are serpiginous or curvilinear gray lesions formed by the advancing mite, are the classic finding seen in nearly 75% of patients (Figure 1).12 Vesicular lesions are more commonly seen in infants and young children, and nodular lesions are significantly more common in infants with a predilection for the axillae and the back.12 In general, lesions tend to be distributed on the interdigital web spaces, flexural wrists, axillae, peri-areolar, periumbilical, and genital areas (Figure 2).11 Infants and children are more likely to have face, scalp, and plantar involvement compared to adolescents and adults (Figure 3).12

(A) Scabies burrow. (B) Dermoscopic image of a scabies burrow.

Figure 1.

(A) Scabies burrow. (B) Dermoscopic image of a scabies burrow.

(A) Scabies involvement of the hands, including (B) the interdigital webbed spaces.

Figure 2.

(A) Scabies involvement of the hands, including (B) the interdigital webbed spaces.

Scalp involvement in an infant with scabies.

Figure 3.

Scalp involvement in an infant with scabies.

Crusted scabies most often affects immunocompromised patients, those with physical or intellectual disability, or those with sensory or motor neuropathy.11 Although pruritus is a prominent symptom in classic scabies, pruritus is minimal in crusted scabies. Patients present with scaly papules or plaques that progress to a generalized distribution and, occasionally, erythroderma.13 Over time, thick adherent hyperkeratotic crust develops (Figure 4). Onychodystrophy with subungual hyperkeratosis is often present and may persist after treatment, representing an important cause of relapse.14 Secondary bacterial infections are frequent complications resulting from the impaired skin barrier.11,13

Crusted scabies.

Figure 4.

Crusted scabies.

Due to its varying morphologies, scabies may mimic many conditions, including impetigo, arthropod bites, papular urticaria, seborrheic dermatitis, Langerhans cell histiocytosis, and infantile acropustulosis. Of note, infantile acropustulosis, which presents as recurrent crops of pruritic vesiculopustules on acral surfaces, may be due to a post-scabetic hypersensitivity response (Figure 5).15 Crusted scabies may mimic psoriasis, and nail scabies may be confused for onychomycosis.13,14 The gold standard for diagnosis is skin scraping with mineral oil preparation and visualization of the mite, eggs, and/or feces (Figure 6).16

Acropustulosis of infancy.

Figure 5.

Acropustulosis of infancy.

Scabies mite, egg, and scybala (feces) visible on mineral oil preparation.

Figure 6.

Scabies mite, egg, and scybala (feces) visible on mineral oil preparation.

Due to its superior efficacy and favorable side effect profile, permethrin 5% cream is the treatment of choice for classic scabies. In infants and young children, the topical cream should be applied to the entire body, including the face and scalp, and left on for 8 to 12 hours before rinsing.11 Nails should be cut, cleaned, and treated with permethrin. A repeat treatment 4 to 7 days later is recommended.11 While the permethrin 5% cream is only approved for children age 2 months and older, it has been used safely and effectively in neonates.11 Other topical treatments, such as malathion 0.5% lotion, crotamiton 10% cream, lindane 1% lotion, and benzyl benzoate, have fallen out of favor due to lower efficacy or unfavorable side effect profiles.

Oral ivermectin is often used as an off-label treatment at a dose of 200 mg per kg given either as a single dose (70% effective) or two doses 1 to 2 weeks apart (95% effective).11 Ivermectin is generally not recommended in children younger than age 5 years or weighing <15 kg due to limited safety data. However, one review of the literature suggests that ivermectin is well tolerated even in this population, without serious or long-term side effects.17 Due to a high incidence of treatment failure in crusted scabies, a combination of oral ivermectin and topical permethrin therapy is often used. Post-scabetic pruritus may persist for up to 4 to 6 weeks after treatment and can be addressed with medium-potency topical steroids and antihistamines.11

All household contacts should be treated regardless of symptoms to minimize risk of relapse. Eliminating fomites is another essential part of preventing treatment failure. Floors, furniture, and mattresses should be vacuumed, and clothing and linens should be cleaned in hot wash and dry cycles. Pets do not need to be treated.

Other types of mite infestations are described in Table 2.18

Other Mite Infestations

Table 2.

Other Mite Infestations

Fleas

Fleas (Siphonaptera) are parasitic arthropods that affect humans (Pulex irritans), cats (Ctenocephalides felis), dogs (Ctenocephalides canis), and rats (Xenopsylla cheopsis).19 Fleas act as vectors for a variety of infections, including endemic typhus, rickettsial diseases, and bubonic plague. They survive by feeding on the host's blood, resulting in pruritic erythematous, edematous papules, vesicles or bullae, distributed on exposed areas, particularly the lower legs (Figure 7). Because fleas are wingless and either jump or crawl from place to place, bites are often seen in a linear or triangular configuration, known as the “breakfast, lunch, and dinner” sign (Figure 8).20 Management focuses on symptom control with topical steroids and antihistamines. Elimination of fleas, by treating pets and cleaning the home, is critical.19

Excoriated flea bites.

Figure 7.

Excoriated flea bites.

“Breakfast, lunch, and dinner” sign.

Figure 8.

“Breakfast, lunch, and dinner” sign.

Bed Bugs

Bed bugs (Cimex lectularis) are parasitic nocturnal insects that feed on blood. The recent resurgence of bed bug infestations in developed countries has been attributed to increasing international travel and insecticide overuse and resistance.21 Bed bugs are red-brown, oval-shaped insects, approximately 5 mm long. They are typically found in warm, dark locations, particularly in the seams of mattresses, furniture, and flooring, and they may be transported from one location to another via travelers' luggage. Existing studies have not confirmed bed bugs as vectors for any infection.21

Clinically, bed bug bites manifest with a small hemorrhagic punctum.21 Hypersensitivity results in pruritic, erythematous, edematous papules.22 As with flea bites, lesions follow the “breakfast, lunch, and dinner” pattern.20 Bite reactions on the eyelids should raise suspicion for bed bugs.23 Bullous lesions may occur, and scratching may lead to secondary bacterial infection.22 Treatment of active lesions is supportive, and the most essential aspect of management is eradicating bed bugs from the home. Nonchemical methods of eradication include manual removal with a vacuum cleaner, enclosing infested items in plastic and discarding, or exposure to higher temperatures (45°C to 48°C) through a dryer or steamer.22 Chemical insecticides may be employed. For persistent infestations, professional exterminators are often required.

Papular Urticaria

Papular urticaria is a common, chronic, recurrent eruption of childhood resulting from delayed-type hypersensitivity to insect bites.24 Bedbugs, mites, fleas, and mosquitoes have all been implicated.25 Affected patients develop intensely pruritic, erythematous, edematous papules and vesicles on exposed areas (Figure 9). Individual lesions may last for several days to weeks, resolving with post-inflammatory hyperpigmentation. With ongoing exposure to the inciting agent, the eruption often recurs, and old lesions may become re-inflamed. The eruption persists until the exposure is removed or until the child becomes desensitized to the inciting agent.24

Papular urticaria.

Figure 9.

Papular urticaria.

Papular urticaria is often distressing due to the difficulty in identifying the trigger. Families may be confused that only one household member is affected despite all being exposed to the offending insect. Because papular urticaria represents a hypersensitivity, only those who are sensitized will react.24 In most cases, the diagnosis can be made based on history and physical examination.

Treatment of papular urticaria can be frustrating and relies on the “3 P's” (prevention, pruritus control, and patience).24 Insect bite prevention, including clothing and repellent, is discussed below. Pets should be examined for fleas. Professional exterminators may be required. Pruritus control consists of topical steroids and antihistamines. Lastly, clinicians should emphasize the chronic, recurrent nature and reassure that symptoms eventually resolve over time.24

Insect Repellents

General protective measures for preventing insect bites include avoiding areas infested with insects; wearing long sleeves, long pants, and closed shoes; and taking measures to control the insect population.26 A variety of chemical and plant-based insect repellents are effective, including most containing N, N-diethyl-meta-toluamide (DEET), picaridin, 2-undecanone, oil of lemon eucalyptus, oil of citronella, catnip oil, or IR 3535 (3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester).

DEET is the most widely used repellent and thought to be the most effective. DEET forms a vapor barrier that prevents mosquitoes, ticks, flies, and other small insects from coming into contact with the skin.26 It is available in a variety of formulations, including sprays, lotions, creams, and wipes.26 The concentration of DEET in these products ranges from 5% to 100% with higher concentrations associated with increased duration of protection. While products containing 5% DEET provide protection for approximately 2 hours, products with 30% DEET provide protection for up to 6 hours.26 A plateau in efficacy has been noted with concentrations higher than 50%.26

When used appropriately, products containing 20% to 30% DEET are felt to be safe for use in infants older than age 2 months and in children (Table 3).26 Adverse effects from DEET use are generally related to excessive use or exposure via nontopical routes (ocular, oral, inhaled, or dermal), with ocular irritation being most common.27 When following guidelines for safe use, severe toxicity remains low, occurring in less than 0.1% of users and more often in adults compared to children.27

Safe Use of Insect Repellents in Children

Table 3.

Safe Use of Insect Repellents in Children

Picaridin is another widely used insect repellent thought to have similar efficacy to DEET, although direct comparison studies are lacking.28 Available concentrations range from 5% to 20% with the latter providing up to 12 hours of protection.26 No serious toxicity has been noted with picaridin, which is odorless, does not damage fabrics, and less likely to irritate the skin.28 Use of picaridin-containing products is not recommended for children younger than age 2 years.28

Plant-derived insect repellents typically contain essential oils, such as oil of lemon eucalyptus, citronella oil, soybean oil, or geraniol.28 Generally, plant-based products do not provide as much protection as the synthetic repellents.26 Oil of lemon eucalyptus is available in a concentration of 40%, which has been shown to have similar efficacy to lower concentrations of DEET, providing 4 to 7 hours of protection against mosquitoes and flies but no tick protection.26,28

References

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  2. American Academy of Pediatrics. Pediculosis corporis (body lice). In: Kimberlin DW, Brady MT, Jackson MA, Long SS, eds. Red Book: 2018 Report of the Committee on Infectious Diseases. 31st ed. Itasca, IL: American Academy of Pediatrics; 2018:612.
  3. American Academy of Pediatrics. Pediculosis pubis (pubic lice, crab lice). In: Kimberlin DW, Brady MT, Jackson MA, Long SS, eds. Red Book: 2018 Report of the Committee on Infectious Diseases. 31st ed. Itasca, IL: American Academy of Pediatrics; 2018:613.
  4. Connor CJ, Selby JC, Wanat KA. Severe pediculosis capitus: a case of “crusted lice” with autoeczematization. Dermatol Online J. 2016;22(3):22. PMID:27136626
  5. Brenner S. “Pediculid”: an unusual id reaction to pediculosis capitis. J Am Acad Dermatol. 1985;12(1 Pt 1):125–126. doi:10.1016/S0190-9622(85)80256-5 [CrossRef] PMID:3980794
  6. Ko CJ, Elston DM. Pediculosis. J Am Acad Dermatol. 2004;50(1):1–12. doi:10.1016/S0190-9622(03)02729-4 [CrossRef] PMID:14699358
  7. Jahnke C, Bauer E, Hengge UR, Feldmeier H. Accuracy of diagnosis of pediculosis capitis: visual inspection vs wet combing. Arch Dermatol. 2009;145(3):309–313. doi:10.1001/archdermatol.2008.587 [CrossRef] PMID:19289764
  8. Bowles VM, Hanegraaf S, Ahveninen T, Sidgiddi S, Allenby K, Alsop H. Effect of a new head lice treatment, abametapir lotion, 0.74%, on louse eggs: a randomized, double-blind study. Glob Pediatr Health. 2019;6:2333794X19831295.
  9. Burgess IF, Burgess NA, Brunton ER. Tocopheryl acetate 20% spray for elimination of head louse infestation: a randomised controlled trial comparing with 1% permethrin creme rinse. BMC Pharmacol Toxicol. 2013;14(1):43. doi:10.1186/2050-6511-14-43 [CrossRef] PMID:24004959
  10. Pierzchalski JL, Bretl DA, Matson SC. Phthirus pubis as a predictor for chlamydia infections in adolescents. Sex Transm Dis. 2002;29(6):331–334. doi:10.1097/00007435-200206000-00004 [CrossRef] PMID:12035022
  11. Golant AK, Levitt JO. Scabies: a review of diagnosis and management based on mite biology. Pediatr Rev. 2012;33(1):e1–e12. doi:10.1542/pir.33-1-e1 [CrossRef] PMID:22210934
  12. Boralevi F, Diallo A, Miquel J, et al. Groupe de Recherche Clinique en Dermatologie Pédiatrique. Clinical phenotype of scabies by age. Pediatrics. 2014;133(4):e910–e916. doi:10.1542/peds.2013-2880 [CrossRef] PMID:24685953
  13. Assaf RR, Wu H. Visual diagnosis: severe scaly pruritic rash in an 8-year-old girl with trisomy 21. Pediatr Rev. 2016;37(11):e45–e47. doi:10.1542/pir.2015-0158 [CrossRef] PMID:27803149
  14. Tempark T, Lekwuttikarn R, Chatproedprai S, Wananukul S. Nail scabies: an unusual presentation often overlooked and mistreated. J Trop Pediatr. 2017;63(2):155–159. PMID:27613759
  15. Mancini AJ, Frieden IJ, Paller AS. Infantile acropustulosis revisited: history of scabies and response to topical corticosteroids. Pediatr Dermatol. 1998;15(5):337–341. doi:10.1046/j.1525-1470.1998.1998015337.x [CrossRef] PMID:9796580
  16. Walter B, Heukelbach J, Fengler G, Worth C, Hengge U, Feldmeier H. Comparison of dermoscopy, skin scraping, and the adhesive tape test for the diagnosis of scabies in a resource-poor setting. Arch Dermatol.2011;147(4):468–473. doi:10.1001/archdermatol.2011.51 [CrossRef] PMID:21482897
  17. Wilkins AL, Steer AC, Cranswick N, Gwee A. Question 1: is it safe to use ivermectin in children less than five years of age and weighing less than 15 kg?Arch Dis Child. 2018;103(5):514–519. doi:10.1136/archdischild-2017-314505 [CrossRef] PMID:29463522
  18. McClain D, Dana AN, Goldenberg G. Mite infestations. Dermatol Ther. 2009;22(4):327–346. doi:10.1111/j.1529-8019.2009.01245.x [CrossRef] PMID:19580577
  19. Anderson J, Paterek E. Flea Bites. Treasure Island, FL: StatPearls Publishing; 2019.
  20. Peres G, Yugar LBT, Haddad Junior V. Breakfast, lunch, and dinner sign: a hallmark of flea and bedbug bites. An Bras Dermatol. 2018;93(5):759–760. doi:10.1590/abd1806-4841.20187384 [CrossRef] PMID:30156636
  21. Goddard J, deShazo R. Bed bugs (Cimex lectularius) and clinical consequences of their bites. JAMA. 2009;301(13):1358–1366. doi:10.1001/jama.2009.405 [CrossRef] PMID:19336711
  22. McMenaman KS, Gausche-Hill M. Cimex lectularius (“bed bugs”): recognition, management, and eradication. Pediatr Emerg Care. 2016;32(11):801–806. doi:10.1097/PEC.0000000000000948 [CrossRef] PMID:27811535
  23. Quach KA, Zaenglein AL. The eyelid sign: a clue to bed bug bites. Pediatr Dermatol. 2014;31(3):353–355. doi:10.1111/pde.12332 [CrossRef] PMID:24649832
  24. Hernandez RG, Cohen BA. Insect bite-induced hypersensitivity and the SCRATCH principles: a new approach to papular urticaria. Pediatrics. 2006;118(1):e189–e196. doi:10.1542/peds.2005-2550 [CrossRef] PMID:16751615
  25. Howard R, Frieden IJ. Papular urticaria in children. Pediatr Dermatol. 1996;13(3):246–249. doi:10.1111/j.1525-1470.1996.tb01212.x [CrossRef] PMID:8806128
  26. American Academy of Pediatrics. Prevention of mosquitoborne and tickborne infections. In: Kimberlin DW, Brady MT, Jackson MA, Long SS, eds. Red Book: 2018 Report of the Committee on Infectious Diseases. 31st ed. Itasca, IL: American Academy of Pediatrics; 2018:195–200.
  27. Bell JW, Veltri JC, Page BC. Human exposures to N,N-diethyl-m-toluamide insect repellents reported to the American Association of Poison Control Centers 1993–1997. Int J Toxicol. 2002;21(5):341–352. doi:10.1080/10915810290096559 [CrossRef] PMID:12396679
  28. Katz TM, Miller JH, Hebert AA. Insect repellents: historical perspectives and new developments. J Am Acad Dermatol. 2008;58(5):865–871. doi:10.1016/j.jaad.2007.10.005 [CrossRef] PMID:18272250

US Food and Drug Administration-Approved Topical Treatments for Head Lice

Treatment Age Availability Instructions Comments/Precautions
Permethrin 1% lotion ≥2 months Over-the-counter Apply to damp hair, saturate hair and scalp, leave on for 10 minutes, then rinse. Repeat in 7 to 10 days if live lice seen Repeat treatment at day 9 is optimal. Do not use conditioner
Pyrethrin + piperonyl butoxide ≥2 years Over-the-counter Apply to dry hair, leave on for 10 minutes, then rinse. Repeat in 7 to 10 days if live lice seen Caution if chrysanthemum or ragweed allergy
Malathion 0.5% lotion ≥6 years Prescription Apply to dry hair, leave on for 8–12 hours, then rinse. Repeat in 7 to 9 days if live lice seen, but a single application is usually adequate Flammable (contains 78% isopropyl alcohol); no safety data for children younger than age 6 years
Benzyl alcohol 5% lotion ≥6 months Prescription Apply to dry hair, saturate hair and scalp, leave on for 10 minutes, then rinse. Repeat in 7 to 10 days if live lice seen Avoid in neonates (associated with neonatal gasping syndrome)
Spinosad 0.9% suspension ≥4 years Prescription Apply to dry hair, saturate hair and scalp, leave on for 10 minutes, then rinse. Repeat in 7 days if live lice are seen Superior efficacy to permethrin in one study8
Ivermectin 0.5% lotion ≥6 months Prescription Apply to dry hair, saturate hair and scalp, leave on for 10 minutes, then rinse. No repeat treatment required

Other Mite Infestations

Mite Clinical Presentation Treatment
Chigger (Trombicula alfreddugesi) Pruritic grouped urticarial papules, papulovesicles, pustules on the popliteal fossae, ankles, toes, and genitalia “Summer penile syndrome” in young boys (dysuria, swelling and pruritus of the genital area) Vector for scrub typhus Prevention (insect repellent), symptomatic treatment (antihistamines, topical anesthetics, topical steroids)
Walking dandruff (Cheyletiella) Dandruff, alopecia, or dermatitis in cats and dogsGrouped pruritic papules, urticarial wheals, bullous lesions, or dermatitis in humans Improves within 3 weeks of infested pet being treated with ectoparasitic shampoo
Straw itch mite (Pyemotes tritici) Pruritic urticarial papules with surrounding pinpoint vesicles and pustules on covered sites Self-limited if source of mites is removed; symptomatic treatment (topical steroids, antihistamines)
House dust mite (Dermatophagoides) Exacerbation of atopic dermatitis, asthma, and allergic rhinitis Reduction of mite population
House mouse mite (Liponyssoides sanguineus) Vector for rickettsialpox; eschar at site of bite followed by fever and generalized papulovesicular eruption Self-limited; occasionally doxycycline or other antibiotics
Avian mite (Dermanyssus, Ornithonyssus) Painful or pruritic papules, vesicles, or urticarial plaques; generalized eczematous dermatitis Symptomatic treatment (topical steroids, antihistamines), removal of exposure
Demodex folliculorum, Demodex brevis Normal flora of facial skin Overgrowth implicated in rosacea Papulopustular eruption (folliculitis) in immunocompromised patients Topical sulfur, topical metronidazole, topical permethrin, topical or oral ivermectin

Safe Use of Insect Repellents in Children

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Apply repellents only to exposed skin or clothing and use just enough to cover these exposed areas

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Do not apply repellents over cuts or irritated skin

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When using sprays, spray on hands first and then apply to face

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Do not apply repellents to eyes, mouths, or hands

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Adults should apply repellents to their own hands first and then spread on the child's exposed skin. Children should not handle the repellent themselves

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Do not use spray repellents in enclosed areas or near food

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Wash hands after application of repel- lents to avoid exposure to the eyes or ingestion

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Once inside, wash all exposed areas with soap and water to avoid prolonged use

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When using sunscreen, sunscreen should be applied to exposed areas first followed by repellent. Combined products with sunscreen and repellent should be avoided

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Authors

Sonia Kamath, MD, is an Assistant Professor of Clinical Dermatology, Keck School of Medicine, University of Southern California; and an Attending Physician, Division of Dermatology, Children's Hospital Los Angeles. Brandi Kenner-Bell, MD, is an Assistant Professor of Dermatology and Pediatrics, Northwestern University Feinberg School of Medicine; and an Attending Physician, Division of Dermatology, Ann and Robert H. Lurie Children's Hospital of Chicago.

Address correspondence to Brandi Kenner-Bell, MD, Division of Dermatology, Ann and Robert H. Lurie Children's Hospital, 225 E. Chicago Avenue, Box #107, Chicago, IL 60611, email: bmkbell@gmail.com.

Disclosure: The authors have no relevant financial relationships to disclose.

10.3928/19382359-20200214-01

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