English
German
French
Italian
Spanish
Portuguese
Chinese
Lithuanian
EK50.0
2.4.7 Arthropod reactions
Grading & Level of Importance: B
ICD-11
Synonyms
Ticks, stings, arthropod reaction
Epidemiology
Prevalence: hard to estimate because of different types of arthropods and environmental considerations. Most cases do not require medical intervention; more often in tropical climates.
Definition
It is necessary to distinguish between:
- Reactions to toxins from insect, spider, mites and tick bites
- Reactions to bites of parasitic insects, spider, mites and ticks
- Permanent ectoparasites: parasitic insects (or arachnids = mites, ticks) live and/or feed on humans, are highly adapted and may be found on human hosts.
- Temporary-accidental ectoparasites: bite humans by chance, the bite reaction varies greatly, and the parasite is rarely found on patients.
Aetiology & Pathogenesis
Human ectoparasites.
Permanent ectoparasites insects: head louse, clothing louse, pubic louse. Arachnids: Demodex and Sarcoptes scabei. Spiders of different types.
Accidental parasitic insects: bed bugs, fleas, mosquitoes, sandflies, gnats, flies and horse flies.
Accidental parasitic arachnids: ticks, Neotrombicula (see Trombiculosis), bites mites (Dermanyssus), non-burrowing animal mites (Cheyletiellidae = walking mange), animal forms of scabies (Sarcoptidae and others).
Sometimes symptoms may be due to neurotoxins.
Signs & Symptoms
Immediate and delayed reactions at site of sting: erythema, macules, papules, wheals and blisters.
The nature of the reaction depends more on the sensitivity of the victim, rather than the nature of the stinging insect.
Localisation
Exposed skin areas: head, neck, extremities.
Classification
See Aetiology and Pathogenesis.
Laboratory & other workups
None specific.
Dermatopathology
Not necessary.
Course
Varies from self-limited mild local reaction to life threatening anaphylactic reactions.
Complications
Persistent arthropod reaction with other complications: pseudolymphomatous reactions, persistent prurigo nodularis-like lesions, secondary bacterial infection. Arthropod borne systemic infections.
Diagnosis
Clinical features (grouped or linearly arranged pruritic papules, sometimes with central haemorrhagic punctae (purpura pulicans).
Differential diagnosis
For insect bites reactions: folliculitis, impetigo, furuncle, carbuncle, prurigo, dermatitis herpetiformis, erysipelas, blistering diseases.
Prevention & Therapy
Insect bite reaction from parasitic insects: topical antipruritic agents (zinc oxide lotion, anti-pruritic cream, corticosteroid lotions). Antihistamines in special situations of IgE mediated reactions (e.g. mosquitoes).
Prevention: protective clothing, sleep under fine-mesh nets, repellents.
Special
None.
Differential Diagnosis
Podcasts
Tests
- A patient is stung by a bee in the left leg. Soon thereafter he develops generalized pruritus and shortness of breath, followed by respiratory distress, anxiety and then unconsciousness. What degree of severity is this reaction?
- Statement 1 A acute solitary bullous lesion could represent a reaction to an arthropod bites or sting
- Which complications do not fit with arthropod bites and stings?
- Which clinical finding does not fit with an arthropod bite or sting?
- What other disorders enter into the differential diagnostic considerations when a child presents with periorbital edema and erythema, as shown in the picture?
- What are possible complications of arthropod bites and stings?
- Which therapeutic approach is best for a bite or sting with an excessive local reaction?
- Typical clinical features of arthropod bites and stings are:
Comments
Be the first one to leave a comment!