WHO Model Prescribing Information: Drugs Used in Skin Diseases
(1997; 132 pages) [French] [Spanish] View the PDF document
Table of Contents
View the documentPreface
View the documentIntroduction
Open this folder and view contentsParasitic infections
Close this folderInsect and arachnid bites and stings
View the documentMosquitos and other biting flies
View the documentBees, wasps, hornets and ants
View the documentBedbugs and reduviid bugs
View the documentScorpions
View the documentPoisonous spiders
View the documentChiggers or harvest mites
View the documentTicks
Open this folder and view contentsSuperficial fungal infections
Open this folder and view contentsSubcutaneous fungal infections
Open this folder and view contentsBacterial infections
Open this folder and view contentsViral infections
Open this folder and view contentsEczematous diseases
Open this folder and view contentsScaling diseases
Open this folder and view contentsPapulosquamous diseases
View the documentCutaneous reactions to drugs
Open this folder and view contentsPigmentary disorders
Open this folder and view contentsPremalignant lesions and malignant tumours
Open this folder and view contentsPhotodermatoses
Open this folder and view contentsBullous dermatoses
View the documentAlopecia areata
View the documentUrticaria
Open this folder and view contentsConditions common in children
View the documentAcne vulgaris
View the documentPruritus
View the documentTropical ulcers
Open this folder and view contentsAntimicrobial drugs
Open this folder and view contentsAntifugal drugs
Open this folder and view contentsAntiseptic agents
Open this folder and view contentsKeratoplastic and keratolytic agents
Open this folder and view contentsScabicides and pediculicides
Open this folder and view contentsAnti-inflammatory and antipruritic drugs1
Open this folder and view contentsAntiallergics and drugs used in anaphylaxis
Open this folder and view contentsUltraviolet radiation-blocking agents (sunscreens)
Open this folder and view contentsMiscellaneous drugs
Open this folder and view contentsAnnex
View the documentSelected WHO Publications of Related Interest
View the documentBack cover
 

Mosquitos and other biting flies

Aside from being vectors of several of the most important parasitic diseases, including malaria, leishmaniasis, onchocerciasis, filariasis and African trypanosomiasis, mosquitos and other biting flies can induce florid local lesions in susceptible persons. Localized pruritus and urticaria-like papules are the characteristic signs of mosquito bites, while blood-sucking flies induce nodular or haemorrhagic lesions. The muscoid larvae that are responsible for myiasis live parasitically in human tissues. The flies are attracted to festering wounds, ulcers and other necrotic lesions, and they sometimes invade normal tissue. In certain areas of Africa and Central America cutaneous myiasis may occur, which is caused by larvae of the human botfly (Dermatobia hominis). The eggs are laid on the bodies of mosquitos, flies or ticks and subsequently transported to humans. This lesion appears as a folliculitis but exudes a serous fluid, and on close inspection, the larvae may seem to be pulsatile.

Papular urticaria, an insect-related, type IV hypersensitivity reaction, is commonly seen in children in developing countries. It is clinically characterized by crops of pruritic weals that evolve into serum-filled papules and, less frequently, vesicles. Excoriation due to scratching leads to secondary bacterial infections. Spontaneous desensitization usually occurs by the age of 7 years. In tropical climates, mosquitos are the main cause of papular urticaria, whereas flies and bedbugs are the common causes in temperate climates.

Prevention and management

Protection is enhanced by knowledge of the habitat and diurnal activity of the vector. Insect repellents and clothing provide some personal protection.

Screens and bednets impregnated with insecticide can be highly effective when used correctly. Secondary myiasis is rarely seen when good standards of personal hygiene are maintained and wounds are covered to protect them from flies.

For papular urticaria, topical antimicrobials are useful to prevent secondary bacterial infection, and oral antihistamines may relieve the pruritus.

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