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How you can recognize and treat bug infestations in children.

Pruritic bug infestations are a common problem among school-age children, Albert C. Yan, MD, said at a pediatric dermatology meeting sponsored by Rady Children's Hospital-San Diego and the University of California, San Diego.

There are four basic bug infestations--cutaneous larva migrans, carpet beetle dermatitis, scabies, and lice--and it is essential for you to be able to recognize and treat these appropriately. You also need to know resistance patterns, and how to counsel patient on full treatment protocol.

Cutaneous larva migrans typically present with a skin rash on the feet or thighs of children and young adults who walk around barefoot. The organism invades through the skin of the foot and creates serpiginous patterns. Ancylostoma braziliense is the most common species to cause this rash. The parasite is usually trapped by the basement membrane and rarely penetrates to visceral organs. However, rarely it can present in the oral mucosa when contaminated products are placed in the mouth, which is why Dr. Yan tells his own kids "not to eat things off the ground." The treatment for this infection includes ivermectin, albendazole, or thiabendazole.

Carpet beetle dermatitis presents in children with a history of spending lots of time on a carpet, presenting with nondescript itchy patches on skin areas that were in contact with the carpet. Carpet beetle dermatitis is becoming more common on the East Coast. Patients actually can find these beetles, which have tiger-striped coloring and have little prickly hairs that stick out of them, in their carpets. The beetles do not bite; rather, the rash is a reaction from exposure to insect blood or the larval hairs. The adult beetles tend to feed on carpet fabrics, wool, grains of food products, animal material, or nectar and pollen in flowers. The treatment is to get rid of the beetles. To rid the house of the beetles, it is recommended to vacuum, remove contaminated food sources, freeze stuffed animals for 10-14 days, and have an exterminator visit the home. Bringing in fresh-cut flowers from the garden without rinsing them may bring the beetles into the house.

Scabies tends to be an itchy, widespread dermatosis. It is associated with extensive small skin papules scattered across the body with linear or curvilinear burrows and tends to present from the elbows or knees distally, especially in webbed areas, such as between the fingers. Keeping these geographic locations in mind makes it easier to differentiate scabies from hand dermatitis and eczema, said Dr. Yan, chief of pediatric dermatology at Children's Hospital of Philadelphia and professor of pediatrics and dermatology at the University of Pennsylvania, Philadelphia.

To help diagnose this infestation, scrape the lesion and visualize the mite, the scybala or mite feces, or the oval eggs under the microscope.

The treatment is a "permethrin party." Luckily, the scabies mite has very little documented resistance to permethrin 5% cream. However, with recurrent treatment, resistance starts to develop, he said. Proper administration is critical in controlling the infestation. For an adult, use 3 ounces or one tube, and for a child, use about 1.5 ounces for a child or one-half a tube. Apply it to the skin from neck down, leave it on for 8 hours overnight. Treat the patient and family members or close contacts. Repeat this application in 1 week. Oral ivermectin is effective and is useful in older kids who may not adhere to the permethrin.

A commonly encountered problem is apparent treatment failure. The scabies may be identified, treated, and then they appear to recur. Some patients have persistent postscabetic itch--the patients are still itchy afterward, but the lesions look excoriated and different than the original scabies lesions. The patient does not need retreatment, Dr. Yan emphasized. Rather, use topical corticosteroids or antihistamines to treat the itch.

Another explanation is improper use of medication--for instance, only certain parts of the skin were treated or all family members had not been treated. In this case, everyone needs to be retreated, he said. Reinfection is possible, but resistance is unlikely. Patients with scabies sometimes develop scabetic nodules or hypersensitivity nodules. Often, these are leftover areas of inflammation that can remain for up to 1 year. Dr. Yan recommends treating these areas with low-dose topical steroids.

The last phenomena presents with recurrent crops of pustules in the acral area, which is acropustulosis of infancy or postscabetic pustulosis. This is a variant of acropustulosis of infancy, in that it is more likely to involve the torso than is traditional acropustulosis and tends to be cyclical in that it reappears every few weeks.

Head lice are an "easy" diagnosis, and Dr. Yan describes finding the actual lice on a patient's head as "very satisfying." They are usually found behind ears, on the posterior aspect of the head, and on the neck. Head lice are very common, affecting approximately 6-12 million people per year, and $100 million is spent annually on treating these infestations. It is more common in 3- to 12-year-old girls, usually more prevalent with longer hair, and is spread primarily through direct contact. Live nits are 1-2 mm from scalp, hatch about 1 week later, live for 1 month, then reproduce, while the original nits die off. The lice cannot survive more than 1-2 days off the human body. Infestations tend to be cyclical throughout the year, with an increased number of cases at the end of school year or during the summer.

Recently, the Journal of Medical Entomology published study findings in which head lice genetics were assessed, raising the concern about the development of "super lice." However, this information has not yet brought treatment changes.

The conventional treatments include Nix, Rid, Triple X, but there can be a fair amount of resistance with these OTC treatment. Other options include mayonnaise and olive oil, however, not much data support the efficacy of this treatment. There are three prescription medications available: benzyl alcohol lotion, spinosad topical suspension, and ivermectin lotion. Start with these treatments quickly when dealing with lice that are resistant. Oral ivermectin also is effective. Dr. Yan concluded his lecture with discussion of other techniques that have been cleared by the Food and Drug Administration, such as blow-drying the lice off the head, if one is okay with them landing in the office!

Dr. Yan reported no relevant financial disclosures.

pdnews@mdedge.com

COMMENTARY BY DR. SIDBURY

THE FIRST QUESTION many parents ask after receiving a diagnosis of "bug bites" is "which bug?" This can be an impossible question to answer making a sometimes-fraught discussion (this diagnosis is not always well received) more difficult. The second point parents emphasize when diagnostic doubt arises is the lack of other affected family members; this would seem contrary to a biting pest in the house. My co-conspirator Dr. Eichenfield once taught me to preempt this doubt by leading with the fact that often only one family member is affected. A bite reaction is just that: a bite followed by a hypersensitivity response manifesting as itch and rash. As with any hypersensitivity reaction, some individuals will react and some will not.

Dr. Albert C.Yan helps us further by describing suggestive features of different types of "arthropod assault." Cutaneous larva migrans declares itself by distribution: typically, the foot of a patient who has gone shoeless in an endemic area. Likewise carpet beetle dermatitis presents with itchy red patches at exposed sites; the beetles do not bite but some children react to exposure. Scabies infestation causes a range of cutaneous manifestations both acutely and subacutely. Telltale burrows or linear lesions on the palms and soles, wrist, interdigital web spaces, and even genitalia are more diagnostically helpful (and where any scrapings should be done ideally) than are more nondescript papules.

Pediatricians should remember that symptoms of itch can persist for days to weeks after successful treatment and topical corticosteroids or emollients help most. Further removed from active infection, some children will develop recurrent crops of extremely pruritic papules and pustules, especially on the feet called acropustulosis weeks to months after treated infection; a more nodular hypersensitivity reaction called "postscabetic nodules" also can occur and may take months to years to fully resolve. Awareness of earlier scabies infections can allay what otherwise can appear to be morphologically distinct and concerning lesions.

Head lice remain the least harmful "dreaded" diagnosis of the elementary school parent. Diagnosis is typically straightforward as children, especially girls aged 4-12 years, have new onset scalp itching especially behind the ears and at the occiput. Over-the-counter pyrethrin-based therapies still are first line but resistance is common. Treatment failure may result from inadequate nit combing as this can be a time-consuming and exacting task, especially in children with long hair. Dr. Yan highlights some of the treatment alternatives including topical ivermectin lotion, which has ovicidal properties, but alas, we do not yet have a single-use magic bullet short of head shaving for all cases of head lice.

Please Note: Illustration(s) are not available due to copyright restrictions.

Caption: DR. YAN

Caption: Pediculus humanus capitis, the head louse, is an Insect of the order Anoplura and is an ectoparasite whose only host is humans.
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Author:Borok, Jenna
Publication:Pediatric News
Date:Jun 1, 2018
Words:1516
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