[Ectoparasites. Part 2: Bed bugs, Demodex, sand fleas and cutaneous larva migrans]. / Ektoparasitosen. Teil 2: Bettwanzen, Haarbalgmilben, Sandfloh und Larva migrans cutanea.

Ectoparasites or epidermal parasites include a very heterogenous group of infections of the outer layers of the skin. Worldwide the most common are scabies, lice, tungiasis, and hookworm-induced cutaneous larva migrans. In recent years, bed bug infestations in hotels or vacation homes seem to have become more frequent. Demodex folliculorum and Demodex brevis are found in the facial and scalp hair follicles in 95% of individuals. Classic Demodex folliculitis is often overlooked in differential diagnostic considerations. This inflammatory sebaceous gland disease as well as Demodex blepharitis both provide a diagnostic and therapeutic challenge. Permethrin can be used topically against demodicosis. Vacationers who go barefoot on beaches in tropical Africa, South America and subtropical Asia risk infestations from female sand fleas. The lesions can be curetted or removed with a punch biopsy, then treated with antiseptics or even systemic antibiotics if a secondary infection develops. Cutaneous larva migrans is one of the most common imported ectoparasite infections from the tropics. Topical treatment measures include thiabendazole or cryotherapy. If the infestation is severe, systemic antihelminthics or ivermectin can be employed.

[Ectoparasites. Part 1: lice and fleas]. / Ektoparasitosen. Teil 1: Läuse und Flöhe.

Ectoparasites and epidermal parasitic skin diseases are a heterogeneous group of infections of the external layer of the skin. The most common forms world-wide are scabies, lice (Pediculosis capitis, corporis, vestimentorum and pubis), tungiasis and the hookworm-associated Larva migrans cutanea. The head louse is the most widespread parasite in children in Germany. The symptoms, apart from pruritus, eczematous skin eruptions and ictus reactions of the skin, are often unspecific and many differential diagnoses must be considered. Treatment of ectoparasites includes manual procedures, such as repeated cleansing and combing out of lice-infected hair and also local antiparasitic treatment with permethrin, pyrethrum extract, allethrin and dimeticon. Lindan which has been used for decades can no longer be used in medications after 2008 after a decision of the EU Commission. Failure of treatment of head lice can be a result of errors in the treatment which favor survival of the eggs, larvae or adults. This can be a result of too short reaction times and too economical use or unequal distribution of medications, excessive dilution due to wet hair or omitting repeated treatment stages. Additionally resistance of head lice to pyrethrum is a known phenomenon and has been reported in several countries.