JAAD online

Ovicidal efficacy of high concentration dimeticone: A new era of head lice treatment

Pediculosis is an infestation of lice on the body, head, or pubic region that occurs worldwide. Lice are ectoparasites of the order Phthiraptera that feed on the blood of infested hosts. Their morphotype dictates their clinical features. Body lice may transmit bacterial pathogens that cause trench fever, relapsing fever, and epidemic typhus, which are potentially life-threatening diseases that remain relevant in contemporary times. Recent data from some settings suggest that head lice may harbor pathogens. The epidemiology, clinical manifestations, and management of body, head, and pubic louse infestation are reviewed. New therapies for head lice and screening considerations for pubic lice are discussed. Tungiasis is an ectoparasitic disease caused by skin penetration by the female Tunga penetrans or, less commonly, Tunga trimamillata flea. It is endemic in Latin America, the Caribbean and sub-Saharan Africa and seen in travelers returning from these regions. Risk factors for acquiring tungiasis, associated morbidity, and potential strategies for prevention and treatment are discussed.

Los piojos de la cabeza o pediculosis capitis son una patología muy prevalente que causa mucha angustia, sobre todo en los padres de niños afectos. En los últimos años se ha demostrado la aparición de muchas resistencias a los tratamientos existentes, debido principalmente al uso indiscriminado de estos.

Presentamos una revisión de la infestación por piojos y de los tratamientos existentes actualmente.

Head lice is a common condition, and it causes great concern in parents of the affected child. Resistance to the most common treatment has been reported recently, due to an indiscriminate use.

A review is presented on this condition and its available treatments.

Epidermal parasitic skin diseases encompass scabies, pediculosis, cutaneous larva migrans, myiasis, and tungiasis. Tungiasis is probably the most neglected of all Neglected Tropical Diseases (NTD). It occurs in South America, the Caribbean and Sub-Saharan Africa and affects marginalized populations where people live in extreme poverty. In endemic communities the prevalence can be up to 30% in general population and 85% in children. Over time, chronic pathology develops characterized by hyperkeratosis, edema around the nail rim, fissures, ulcers, deformation and loss of nails. This leads to a pattern of disabilities, eventually resulting in impairment of mobility.

Dimeticones are a family of silicon oils with a potential to kill parasites located on top or inside the epidermis by a physical mode of action. They are considered the treatment of choice for pediculosis capitis and pediculosis pubis. With regard to tungiasis, the so called rear abdominal cone of the parasites has been identified as a target for treatment with dimeticones. NYDA®, a mixture of two dimeticones with different viscosity, is the only dimeticone product for which data on the mode of action, efficacy and safety with regard to tungiasis exists. The product has been shown highly effective against embedded sand fleas, even in very intense infection with more than 500 parasites situated on top of each other. A randomized controlled trial showed that seven days after a targeted application of NYDA® 97% (95% CI 94–99%) of the embedded sand fleas had lost all signs of viability.

Comprehensive toxicological investigations on the dimeticones contained in NYDA® showed that there is practically no risk of embryotoxicity, fetotoxicity, teratogenicity, and other toxicity. The safety of dimeticones was also demonstrated in clinical trials with a total of 106 participants with tungiasis, in which not a single adverse event was observed.

These are cutaneous diseases caused by insects, worms, protozoa, or coelenterates which may or may not have a parasitic life. In this review the main ethological agents, clinical aspects, laboratory exams, and treatments of these dermatological diseases will be studied.