Changes

June 2026 — reviewed. A literature search was conducted in April 2026 to identify evidence-based guidelines, UK policy, systematic reviews, and key randomized controlled trials (RCTs)  published since the last revision of this topic. No major changes to the recommendations have been made, but the topic has been restructured to improve flow and usability.

Update

Goals

To support primary healthcare professionals to:

• Identify, assess, and manage insect bites and stings appropriately in primary care.
• Refer people with severe or systemic reactions to insect bites and stings.
• Provide advice on prevention and avoidance of future insect bites and stings.

Outcome measures

Audit criteria

No audit criteria were found during the review of this topic.

QOF indicators

QIPP - Options for local implementation

No QIPP indicators were found during the review of this topic.

NICE Quality standards

No NICE quality standards were found during the review of this topic.

What is it?

• Insect bites
  • Some insects (such as mosquitoes, bed bugs, and fleas) have mouthparts that pierce the skin with little trauma; bites from these insects may not be noticed immediately.
  • Other insects (such as horseflies and midges) feed by lacerating the skin and lapping pooled blood from the wound; bites from these insects are usually painful and noticed immediately.
  • During feeding, biting insects inject saliva containing anticoagulants, vasodilators, and other biologically active substances that promote blood flow. These substances can cause local skin reactions and, rarely, systemic allergic reactions.
  • Usually, the first time a person is bitten by a particular insect, no reaction occurs (unless the saliva contains a directly toxic substance).
    • Following sensitization, for example after repeated bites, Type IV (cell-mediated or delayed) hypersensitivity reactions may develop 8–72 hours after a bite, causing inflamed, itchy maculopapules that persist for several days.
    • Type I (immediate) hypersensitivity reactions may occur within 20 minutes of a bite, producing a wheal-and-flare response. Rarely, systemic allergic reactions, including anaphylaxis, may occur.
    • With prolonged exposure to bites, progressive desensitization may occur, eventually resulting in little or no skin reaction.
    • Papular urticaria (itchy erythematous papules) is a common reaction to insect bites in children, particularly those with atopic dermatitis.
• Insect stings
  • Stinging insects (such as bess, wasps, and hornets) inject venom into the skin via a barbed or non-barbed stinger, usually as a defensive response. Stings are typically immediately painful.
  • Honeybees and occasionally other stinging insects may leave a barbed stinger and attached venom sac in the skin after stinging.
  • Venom contains allergens (such as hyaluronidase and acid phosphatase) and pharmacologically active substances (such as histamine), which can cause reactions ranging from mild localised pain and erythema to severe systemic reactions, including anaphylaxis.
  • Following sensitisation, subsequent stings may trigger immediate hypersensitivity reactions ranging from large local reactions (oedema, erythema, and pruritus extending more than 10 cm from the sting site and peaking 24–48 hours after the sting) to severe systemic allergic reactions.
  • The antigenic compounds in the venom of bees, wasps, and hornets are more likely to cause severe systemic hypersensitivity reactions than those of most other stinging insects.

[Krishna, 2011; Juckett, 2013; Golden, 2017; Finnikin, 2023]

What causes insect bites and stings?

• Insect bites and stings usually occur as a result of feeding or defensive behaviours.
  • Bites are commonly associated with feeding (for example, by mosquitoes, bed bugs, fleas, and horseflies).
  • Stings are usually a defensive response (for example, from bees, wasps, and ants).
• Risk factors for insect bites and stings include:
  
  • Occupational exposure to insects, for example through beekeeping, farming, or forestry work.
  • Outdoor activities, such as hiking in tick-infested areas, gardening, or picnicking. 
  • Increased skin exposure, for example walking barefoot outdoors.
  • Contact with pets, such as cats or dogs, that may harbour fleas.

[Burns, 2004; Monsel, 2016; Golden, 2017; Wilcock, 2020]

How common are insect bites and stings?

• Insect bites and stings are common.
  
  • A UK general practice study conducted between 1999 and 2003 reported a mean weekly incidence of 5.4 insect bite presentations per 100,000 population [Elliot, 2006]. However, this estimate has not been independently validated, and uncertainty remains regarding the true incidence of insect bites.
  • Insect bites tend to be seasonal and increase during the summer months when more insects are active, and more skin is exposed. In a quality improvement study conducted in general practices in England and Wales [Wilcox, 2023]:
    • A combined practice population of 161,346 recorded 355 consultations for insect bites.
    • About two-thirds of cases occurred in females, with ages ranging from 3 to 89 years.
    • Incidence peaked in July, with a mean weekly incidence of 8 consultations per 100,000 population.
  • Data on the incidence of insect stings are limited. However, questionnaire-based studies suggest that 56–94% of people are stung by insects, such as bees, wasps, or ants, at least once in their lifetime [Krishna, 2011].
    • Insect stings account for 6.5% of hospital admissions coded as anaphylaxis and 14% of anaphylaxis-related deaths in the UK [Resuscitation Council UK, 2021a].

[Krishna, 2011; DTB, 2012; Wilcock, 2020]

Complications of insect bites and stings

• Complications of insect bites and stings include:
  
  • Allergic reactions, ranging from large local reactions to systemic allergic reactions (anaphylaxis).
  • Systemic toxicity following multiple stings, resulting from the direct effects of venom rather than an allergic reaction. This is most commonly associated with multiple bee or wasp stings and may cause nausea, vomiting, diarrhoea, headache, hypotension, shock, and, rarely, death.
  • Transmission of infectious diseases, such as Lyme disease. For more information see the CKS topic on Lyme disease.
  • Secondary bacterial infection, such as cellulitis and impetigo. For more information, see the CKS topics on Cellulitis - acute and Impetigo.
  • Exacerbation of pre-existing skin conditions, including atopic eczema.
  • Psychological distress associated with infestations, such as bed bugs and scabies.
  • Rare complications, including serum sickness-like reactions, vasculitis, neuritis, encephalitis, nephrotic syndrome, and acute coronary syndromes (Kounis syndrome).

[Krishna, 2011; Golden, 2017; Wilcock, 2020; Resuscitation Council UK, 2021a; Ruëff, 2023; Zisa, 2023]

Prognosis

• Most insect bite reactions are self-limiting and resolve within hours to several days. Occasionally, symptoms may persist for weeks or months, for example when:
  • Tick mouthparts are retained in the skin after removal, resulting in persistent granulomatous papules or nodules.
  • Bedbug, flea, lice, or scabies infestations remain untreated, causing ongoing symptoms, psychological distress, and secondary bacterial infection.
• Most insect stings result in small local reactions. In some people, large local reactions or systemic allergic reactions may occur.
  • Potentially life-threatening systemic reactions to insect stings are uncommon, occurring in an estimated 0.4–0.8% of children and up to 3% of adults.
  • The risk of future systemic reactions depends on the severity of previous sting reactions:
    • In people with a history of large local reactions, the risk of a future systemic reaction is estimated to be 4–10%.
    • Approximately 14–20% of people who have had a mild systemic reaction will experience another systemic reaction if re-stung.
    •  In people who have had anaphylaxis following an insect sting, the risk of recurrent anaphylaxis following a subsequent sting is estimated to be up to 70%.

[Liberman, 2015; Monsel, 2016; Golden, 2017]

How should I assess a person with a suspected insect bite or sting?

• Take a history. Ask about:
  • Presenting symptoms, including:
    • Onset, site, duration, and progression.
    • Local symptoms, such as pain, swelling, erythema, and itching.
    • Systemic symptoms, such as urticaria, rhinitis, wheezing, abdominal pain, vomiting, and dizziness.
  • Possible exposure to insects, including:  
    • Risk factors for insect bites or stings, such as occupation, contact with domestic pets, camping, gardening, or walking in wooded/heath areas.
    • Witnessed exposure to a bite or sting from a specific insect. Consider potential pathogens transmitted by specific insects, such as Lyme disease associated with tick bites. For more information, see the CKS topic on Lyme disease.
  • Relevant medical history, including:
    • Previous serious reactions to insect bites or stings.
    • Use of over-the-counter and prescribed preparations. In some people, topical preparations can cause allergic or sensitivity reactions.  
• Examine the person. Look for:
  • Signs of systemic hypersensitivity reaction (SR). SRs usually develop rapidly within minutes of a sting. Clinical features may include:
    • Mild SR: pruritus, urticaria, erythema, mild angioedema, rhinitis, and conjunctivitis.
    • Moderate SR: mild asthma symptoms, moderate angio-oedema, abdominal pain, vomiting, diarrhoea, and mild, transient lightheadedness or dizziness.
    • Severe (potentially life-threatening) SR: swelling of the mucous membranes, airway compromise (such as bronchospasm or laryngeal oedema), hypotension, tachycardia, collapse, or loss of consciousness.
  • Signs of a systemic toxic reaction following multiple stings, such as hypotension, severe headache, diarrhoea, vomiting, and shock.
  • Signs of delayed reactions, including urticarial rash or a serum sickness-like reaction with urticaria, arthralgia, and joint swelling developing several hours after a sting.
  • Signs sugestive of a specific insect bite or sting, such as:
    • Bee sting: the stinger may still be visible in the skin.
    • Flea bites: bites from cat or dog fleas are typically found below the knees.
    • Bed bugs: pruritic maculopapular lesions with haemorrhagic puncta may appear on exposed skin about 10 days after a bite. Other presentations include isolated pruritus, nodules, bullae or urticaria. Large numbers of bites can lead to widespread erythema or urticaria. Suspect bed bugs if similar symptoms develop in people sharing a bed or travelling together.
    • Tick bites: the tick may still be attached to the skin. Acute tick bites may appear as an erythematous macule, papule or nodule. Bites from infected ticks may result in Lyme disease, which can present with erythema migrans (sometimes called a bullseye rash). For more information, see the CKS topic on Lyme disease.
    • Horse flies and stable flies: painful bites which may bleed and can become secondarily infected.
    • Midge bites: typically multiple small papular lesions on exposed skin.
    • Spider bites: may leave two puncture marks.
    • Head, body, and pubic lice: can lead to excoriation due to itching caused by louse salivary antigens. For more information see the CKS topics on Head lice and Pubic lice.
• Investigations are not usually required, as the diagnosis of an insect bite or sting can generally be made from the history and examination.
  • Further investigation of severe reactions to insect bites or stings is usually undertaken in secondary care.

Differential diagnosis

• Differential diagnoses for insect bites and stings include:
  • Skin infection, such as abscess, folliculitis, or cellulitis. For more information, see the CKS topic on Cellulitis - acute.
  • Contact dermatitis. For more information, see the CKS topic on Dermatitis - contact.
  • Chickenpox. For more information, see the CKS topic on Chickenpox.
  • Urticaria. For more information, see the CKS topic on Urticaria.
  • Skin cancers, such as basal cell carcinoma, squamous cell carcinoma, melanoma, and Kaposi’s sarcoma. For more information, see the CKS topic on Skin cancers - recognition and referral.
  • Minor skin trauma, such as abrasions or scratches.
  • Plant stings, such as nettle stings.

Scenario: Admission

From age 1 month onwards.

Search strategy

Scope of search

A literature search was conducted for guidelines, systematic reviews and randomized controlled trials on primary care management of insect bites and stings.

Search dates

October 2021 - Arpil 2026

Key search terms

Various combinations of searches were carried out. The terms listed below are the core search terms that were used for Medline.

• exp insect bites and stings/
• insect bite$ or reaction$.kw,ti,ab.

Sources of guidelines

• National Institute for Health and Care Excellence (NICE)
• Scottish Intercollegiate Guidelines Network (SIGN)
• Royal College of Physicians
• Royal College of General Practitioners
• Royal College of Nursing
• NICE Evidence
• World Health Organization
• Guidelines International Network
• TRIP database
• Agency for Healthcare Research and Quality
• National Health and Medical Research Council (Australia)
• Royal Australian College of General Practitioners
• British Columbia Medical Association
• Canadian Medical Association
• Alberta Medical Association
• Michigan Quality Improvement Consortium
• Singapore Ministry of Health
• National Resource for Infection Control
• RefHELP NHS Lothian Referral Guidelines
• Medline (with guideline filter)
• Driver and Vehicle Licensing Agency
• NHS Health at Work (occupational health practice)

Sources of systematic reviews and meta-analyses

• The Cochrane Library:
  • Systematic reviews
  • Protocols
  • Database of Abstracts of Reviews of Effects
• Medline (with systematic review filter)
• EMBASE (with systematic review filter)

Sources of health technology assessments and economic appraisals

• NIHR Health Technology Assessment programme
• The Cochrane Library:
  • NHS Economic Evaluations
  • Health Technology Assessments
• Canadian Agency for Drugs and Technologies in Health
• International Network of Agencies for Health Technology Assessment

Sources of randomized controlled trials

• The Cochrane Library:
  • Central Register of Controlled Trials
• Medline (with randomized controlled trial filter)
• EMBASE (with randomized controlled trial filter)

Sources of evidence based reviews and evidence summaries

• Drug and Therapeutics Bulletin
• TRIP database
• Central Services Agency COMPASS Therapeutic Notes

Sources of national policy

• Department of Health
• Health Management Information Consortium (HMIC)

Patient experiences

• Healthtalk
• BMJ - Patient Journeys

Sources of medicines information

The following sources are used by CKS pharmacists and are not necessarily searched by CKS information specialists for all topics. Some of these resources are not freely available and require subscriptions to access content.

• British National Formulary (BNF)
• electronic Medicines Compendium (eMC)
• European Medicines Agency (EMEA)
• Medicines and Healthcare products Regulatory Agency (MHRA)
• REPROTOX
• Scottish Medicines Consortium
• Stockley's Drug Interactions
• TERIS
• TOXBASE
• Micromedex
• UK Medicines Information

Stakeholder engagement

Our policy

The external review process is an essential part of CKS topic development. Consultation with a wide range of stakeholders provides quality assurance of the topic in terms of:

• Clinical accuracy.
• Consistency with other providers of clinical knowledge for primary care.
• Accuracy of implementation of national guidance (in particular NICE guidelines).
• Usability.

Principles of the consultation process

• The process is inclusive and any individual may participate.
• To participate, an individual must declare whether they have any competing interests or not. If they do not declare whether or not they have competing interests, their comments will not be considered.
• Comments received after the deadline will be considered, but they may not be acted upon before the clinical topic is issued onto the website.
• Comments are accepted in any format that is convenient to the reviewer, although an electronic format is encouraged.
• External reviewers are not paid for commenting on the draft topics.
• Discussion with an individual or an organization about the CKS response to their comments is only undertaken in exceptional circumstances (at the discretion of the Clinical Editor or Editorial Steering Group).
• All reviewers are thanked and offered a letter acknowledging their contribution for the purposes of appraisal/revalidation.
• All reviewers are invited to be acknowledged on the website. All reviewers are given the opportunity to feedback about the external review process, enabling improvements to be made where appropriate.

Stakeholders

• Key stakeholders identified by the CKS team are invited to comment on draft CKS topics. Individuals and organizations can also register an interest to feedback on a specific topic, or topics in a particular clinical area, through the Getting involved section of the Clarity Informatics website.
• Stakeholders identified from the following groups are invited to review draft topics:
  • Experts in the topic area.
  • Professional organizations and societies (for example, Royal Colleges).
  • Patient organizations, Clarity has established close links with groups such as Age UK and the Alzheimer’s Society specifically for their input into new topic development, review of current topic content and advice on relevant areas of expert knowledge.
  • Guideline development groups where the topic is an implementation of a guideline.
  • The British National Formulary team.
  • The editorial team that develop MeReC Publications.
• Reviewers are provided with clear instructions about what to review, what comments are particularly helpful, how to submit comments, and declaring interests.

Patient engagement

Clarity Informatics has enlisted the support and involvement of patients and lay persons at all stages in the process of creating the content which include:

• Topic selection
• Scoping of topic
• Selection of clinical scenarios
• First draft internal review
• Second draft internal review
• External review
• Final draft and pre-publication

Our lay and patient involvement includes membership on the editorial steering group, contacting expert patient groups, organizations and individuals.

Evidence exclusion criteria

Our policy

Scoping a literature search, and reviewing the evidence for CKS is a methodical and systematic process that is carried out by the lead clinical author for each topic. Relevant evidence is gathered in order that the clinical author can make fully informed decisions and recommendations. It is important to note that some evidence may be excluded for a variety of reasons. These reasons may be applied across all CKS topics or may be specific to a given topic.

Studies identified during literature searches are reviewed to identify the most appropriate information to author a CKS topic, ensuring any recommendations are based on the best evidence. We use the principles of the GRADE and PICOT approaches to assess the quality of published research. We use the principles of AGREE II to assess the quality of published guidelines.

Standard exclusions for scoping literature:

• Animal studies
• Original research is not written in English

Possible exclusions for reviewed literature:

• Sample size too small or study underpowered
• Bias evident or promotional literature
• Population not relevant
• Intervention/treatment not relevant
• Outcomes not relevant
• Outcomes have no clear evidence of clinical effectiveness
• Setting not relevant
• Not relevant to UK
• Incorrect study type
• Review article
• Duplicate reference

Organizational, behavioural and financial barriers

Our policy

The CKS literature searches take into consideration the following concepts, which are discussed at the initial scoping of the topic.

• Feasibility
  • Studies are selected depending on whether the intervention under investigation is available in the NHS and can be practically and safely undertaken in primary care.
• Organizational and Financial Impact Analysis
• Studies are selected and evaluated on whether the intervention under investigations may have an impact on local clinical service provision or national impact on cost for the NHS. The principles of clinical budget impact analysis are adhered to, evaluated and recorded by the author. The following factors are considered when making this assessment and analysis.
  • Eligible population
  • Current interventions
  • Likely uptake of new intervention or recommendation
  • Cost of the current or new intervention mix
  • Impact on other costs
  • Condition-related costs
  • In-direct costs and service impacts
  • Time dependencies
• Cost-effectiveness or cost-benefit analysis studies are identified where available. 

We also evaluate and include evidence from NICE accredited sources which provide economic evaluations of recommendations, such as NICE guidelines. When a recommended action may not be possible because of resource constraints, this is explicitly indicated to healthcare professionals by the wording of the CKS recommendation.

Declarations of interest

Our policy

Clarity Informatics requests that all those involved in the writing and reviewing of topics, and those involved in the external review process to declare any competing interests. Signed copies are securely held by Clarity Informatics and are available on request with the permission of the individual. A copy of the declaration of interest form which participants are asked to complete annually is also available on request. A brief outline of the declarations of interest policy is described here and full details of the policy is available on the Clarity Informatics website. Declarations of interests of the authors are not routinely published, however competing interests of all those involved in the topic update or development are listed below. Competing interests include:

• Personal financial interests
• Personal family interest
• Personal non-financial interest
• Non-personal financial gain or benefit

Although particular attention is given to interests that could result in financial gains or losses for the individual, competing interests may also arise from academic competition or for political, personal, religious, and reputational reasons. An individual is not obliged to seek out knowledge of work done for, or on behalf of, the healthcare industry within the departments for which they are responsible if they would not normally expect to be informed.

Who should declare competing interests?

Any individual (or organization) involved in developing, reviewing, or commenting on clinical content, particularly the recommendations should declare competing interests. This includes the authoring team members, expert advisers, external reviewers of draft topics, individuals providing feedback on published topics, and Editorial Steering Group members. Declarations of interest are completed annually for authoring team and editorial steering group members, and are completed at the start of the topic update and development process for external stakeholders.

Competing interests declared for this topic:

None.