Dermatologist addresses common parasitic infestations and latest treatment options at Academy Annual Meeting

If simply the thought of bedbugs, scabies and head lice makes you feel a little itchy, imagine how those affected by these common infestations feel when they learn what has been creeping around them and causing symptoms such as intense itching, red bite marks or irritated scalps. Even less comforting is the fact that some parasitic infestations are on the rise, and can strike adults and children in unsuspecting places.

Speaking today at the 68th Annual Meeting of the American Academy of Dermatology (Academy), dermatologist Albert C. Yan, MD, FAAD, chief of dermatology at the Children's Hospital of Philadelphia and associate professor in the departments of pediatrics and dermatology at the University of Pennsylvania, addressed the prevalence of bedbugs, scabies and head lice, and the latest treatments for the skin and hair problems they can cause for their unsuspecting prey.

Don't Let the Bedbugs Bite: Infestations are on the Rise

In recent years, infestations of Cimex lectularius (commonly referred to as bedbugs) have become a significant health nuisance. These nocturnal, reddish-brown wingless insects are visible to the naked eye, measuring between 3-5 mm in size, have three pairs of legs and feed on blood. Dr. Yan reported that the increased incidence of bed bugs is likely due to a rise in international travel and the elimination of the pesticide DDT, which had been highly effective in destroying this insect. In fact, studies have shown that the resistance to currently available pesticides has contributed to a 500 percent increase in the population of bedbugs in the past few years alone.

"In the United States, bed bugs frequently infest hotels and homes and, once established, can spread rapidly and be difficult to eliminate," said Dr. Yan. "For example, New York City reports hundreds of complaints of bedbug infestations every year, and these numbers have been steadily increasing. In addition, in two separate surveys of hotels done by extermination companies, reports have emerged indicating that 14 percent of hotel rooms and up to 25 percent of hotels show evidence of bedbug infestation."

Bedbugs are hardy insects and can go as long as six to 12 months between feedings in times when their food supply is scarce. They commonly are found along the seams of mattresses or box springs, behind headboards, or in other small dark spaces. When bedbugs bite, people may experience intense itching that can be hard to relieve.

"About one-third of people bitten by bedbugs will develop juicy bite reactions that are often clustered in groups, which dermatologists refer to as a 'breakfast, lunch and dinner' pattern," said Dr. Yan. "However, bedbugs have not thus far been associated with any serious health threats nor have there been any documented cases of diseases being transmitted from bedbugs."

Dr. Yan noted that topical corticosteroids are effective in reducing the itching and redness of bedbug bites, and warm compresses applied directly to the bites can help ease itching.

To avoid bedbugs, it is recommended that individuals check their hotel room before unpacking, especially along the seam of the mattress and in the bed sheets and linens. Never put your suitcase on the floor and if you are using the luggage rack in the room, check it thoroughly for signs of bugs. Once home, wash or dry clean your items immediately and check your suitcase for any signs that you have brought the bugs back with you.

Itching for Relief from Scabies

Scabies is another common infestation caused by a tiny, round eight-legged mite that burrows in the skin and can cause intense itching. Little red bumps similar to hives, tiny bites or pimples usually appear with scabies and, in some cases, the skin can become crusty or scaly, especially between fingers and toes. Some people also can develop nodular lesions from a hypersensitivity reaction, which can be seen in the armpit or genital areas.
Dermatologists estimate that more than 300 million cases of scabies occur around the world every year, and it is easily transmitted from person to person by close contact. Although everyone is susceptible to scabies, crowded living conditions and poor hygiene are two of the most common associations.

"Dermatologists can diagnose scabies by doing a thorough examination of the patient, and sometimes the diagnosis can be confirmed by scraping the lesions to identify the scabies mites or its eggs," said Dr. Yan. "Recently, use of epiluminescence microscopy (dermatoscopy) also has demonstrated good sensitivity for identifying mites by looking for a specific pattern that indicates the pigmented areas of mites, as well as looking for corroborating air bubbles associated with the mite's presence."

The gold standard treatment for scabies remains topical 5% permethrin cream for most patients who are three months old or older. For younger children or pregnant women, sulfur compounds in petrolatum can be effective in treating scabies. Dr. Yan added that the oral medication ivermectin also has been shown to be effective, particularly for resistant cases or those with extensive infestations, but should not be used for pregnant women or young children. New therapies on the horizon focusing on the use of terpineols and tea tree oil have shown promise in early studies.

Not having close skin-to-skin contact with someone who has scabies or with their personal items (such as clothes, towels, and brushes) will help avoid contracting the condition.

Head Lice: Treating Parasites That Go to Your Head

According to studies, 6 million to 12 million people a year suffer from head lice infestation, and it is estimated that more than $100 million is spent annually to combat this problem. Head lice tend to affect younger, school-aged children, and girls tend to get head lice more than boys due to their longer hairstyles.

The most common sign of head lice is an itchy scalp, and red bumps and small tears in the skin in the affected areas. Dr. Yan noted that close examination of the hair and scalp will show evidence of the egg casings (or nits) attached to the hair shafts, as well as live lice. The nits hatch within seven to 10 days and live about 30 days, during which they reproduce to spread the infestation.

Traditional treatments for head lice include the over-the-counter topical treatments permethrin and synthetic pyrethroids. However, Dr. Yan pointed out that resistance to standard pyrethroid treatments has become widespread and is well documented in the United States, the United Kingdom, Israel and the Czech Republic. In addition, one study found that patients using the standard instructions for both permethrin and synthetic pyrethroids - in which patients are instructed to leave the products on the hair for 10 minutes and then wash it out - only killed 5 to 7 percent of head lice.

To help children avoid lice, they should not share combs, brushes, hats, barrettes or any other personal care items with anyone else, regardless of whether they have lice or not. Also, it's important to examine everyone in the household when there is a case of head lice, just to be sure that the bugs have not been transmitted.

"Due to the mounting resistance of head lice to traditional treatments, promising alternative therapies have emerged, including the use of trimethoprim-sulfamethoxazole combined with topical therapies, products that can suffocate the lice, and novel agents or devices that work to physically destroy the lice," said Dr. Yan. "The specific alternative therapy used will depend in large part on the dermatologist's assessment of the safety and efficacy of available therapies and the degree of infestation."

Dr. Yan added that people who experience any unusual rashes, especially those accompanied by itching or inflammation, should consult their dermatologist for proper evaluation and treatment.

Source: American Academy of Dermatology (Academy),