Clinical Parasitology & Parasitic Infections of Dermal and Epithelial Tissues

A vocabulary set summarizing key terms, organisms, diseases, diagnostics, and treatments from the lecture on clinical parasitology and dermal/epithelial parasitic infections.

Eosinophilia

Elevated eosinophil count or infiltrate. Can be due to parasitic, fungal, allergic, or foreign-body reactions.

Enterobius vermicularis

Pinworm; nematode whose eggs can trigger eosinophilic infiltrates and appendicitis in children.

Swimmer’s Itch

Pruritic dermatitis within minutes–24 h after freshwater exposure, caused by bird schistosome cercariae (Trichobilharzia spp.).

Trichobilharzia spp.

Avian schistosomes responsible for swimmer’s itch; self-limiting and treated symptomatically.

Leishmania spp.

Protozoa transmitted by sand flies causing cutaneous, mucocutaneous, or visceral leishmaniasis.

Cutaneous Leishmaniasis

Skin ulcers from Leishmania infection; diagnosed by biopsy showing macrophages full of amastigotes.

Mucocutaneous Leishmaniasis

Progression of cutaneous lesions to mucous membranes leading to disfiguring destruction.

Amastigote

Intracellular, non-flagellated stage of Leishmania found in human macrophages.

Promastigote

Flagellated stage of Leishmania that develops in sand flies and initiates human infection.

Sodium stibogluconate

First-line antimonial drug for many forms of leishmaniasis (Pentostam).

Pentavalent Antimony

Antileishmanial compound not marketed in U.S.; available from CDC for special use.

Liposomal Amphotericin B

Antifungal formulation used especially for visceral leishmaniasis.

Ectoparasite

Parasitic arthropod living on skin surface, e.g., lice, scabies mites, myiasis larvae.

Myiasis

Invasion of skin or wounds by fly larvae, producing boil-like or draining lesions.

Dermatobia hominis

Human botfly causing furuncular myiasis; larva removed surgically or by occlusion.

Cochliomyia hominivorax

New World screwworm; fly larva that invades wounds, eradicated in U.S. but re-emerging south of border.

Chrysomya bezziana

Old World screwworm producing invasive myiasis in Asia and Africa.

Pediculosis capitis

Head-lice infestation by Pediculus humanus capitis causing itchy papular scalp rash.

Pediculosis corporis

Body-lice infestation by Pediculus humanus humanus; associated with poor hygiene & vector of louse-borne diseases.

Phthiriasis pubis

Pubic-lice infestation by Pthirus pubis; sexually transmitted and indicator of possible abuse in children.

Cimex lectularius

Common bedbug; bites in a linear pattern causing itchy papules; no disease transmission proven.

Scabies

Skin infestation by Sarcoptes scabiei producing intensely itchy vesicles and burrows, especially in folds.

Sarcoptes scabiei

Obligate human mite responsible for scabies; diagnosed by skin scraping or visualization of burrows.

Loiasis

‘Eye-worm disease’ caused by Loa loa; wandering adult worm across conjunctiva, eosinophilia, treated with ivermectin or albendazole.

Onchocerciasis

River blindness from Onchocerca volvulus; blackfly-borne, causes dermatitis and corneal scarring; treated with ivermectin ± doxycycline.

Ivermectin

Antiparasitic that opens glutamate-gated chloride channels in invertebrates, causing paralysis; safe in humans at therapeutic doses.

Acanthamoeba Keratitis

Painful corneal infection in contact-lens users exposed to contaminated water; dendriform epithelium pattern, treated with debridement & biguanides.

Delusional Parasitosis (Ekbom’s Syndrome)

Psychiatric condition with false belief of being infested; must first rule out real parasites, drugs, hormones.

Permethrin

Topical insecticide used to treat lice and scabies infestations.

Secondary Bacterial Infection

Common complication of ectoparasitic skin lesions requiring antibiotic coverage.