CONDITION
Bee and Wasp Stings
A bee or wasp sting is a localised injection of venom through the skin, triggering an immune response that produces swelling, redness, and discomfort at the site. Most stings in dogs and cats result in mild, self-limiting reactions confined to the area of the sting itself—often a paw, face, or mouth if the animal has snapped at or investigated the insect. In some animals, the immune system responds more extensively, producing swelling beyond the immediate area or, rarely, a systemic reaction affecting breathing, circulation, or other organ systems. Owners typically notice sudden pawing at the face, licking at a limb, visible swelling, or a clear point of pain that was not present moments before. The reaction may appear within minutes or develop more gradually over the first hour or two. Stings inside the mouth or throat—common when an animal catches or eats an insect—can produce swelling that is less visible from the outside but may affect breathing or swallowing. This page explores what signals suggest a sting has occurred, the mechanisms underlying local and systemic reactions, how the severity and type of response are assessed, and the range of approaches used to manage reactions of differing intensity and distribution.
Why this matters now
Bee and wasp stings occur most commonly during the warmer months in the UK, typically between late spring and early autumn, when both insects are most active and pets spend more time outdoors. Dogs and cats of any age or breed can be stung, though younger animals and those with higher prey drive or investigative behaviour tend to encounter stinging insects more frequently. Stings to the face and mouth are particularly common in animals that snap at flying insects or investigate them on the ground, whilst paw stings often occur when an animal steps on or disturbs an insect in grass or on hard surfaces.
Most sting reactions develop within minutes of the event, with local swelling and discomfort peaking over the first few hours and then gradually subsiding over one to three days without intervention. In a smaller proportion of cases, the reaction extends beyond the immediate sting site, producing more widespread swelling that may take several days to resolve fully. Systemic reactions, when they occur, typically begin within minutes to half an hour of the sting and may progress over the following hour, though the timeframe and severity vary considerably between individuals. In the more severe form, swelling in the throat can narrow the airway and a fall in blood pressure can lead to collapse, and either can be fatal. After many stings at once, a delayed phase can follow over the next one to three days, in which red blood cells can be destroyed and the kidneys injured. Dark urine, weakness or a reduced appetite in that window can reflect this even after the visible swelling has improved.
Signals & patterns
Early signals
Sudden vocalisation or startle
An animal may yelp, cry out, or react sharply at the moment of the sting, often whilst outdoors or near flowering plants. This vocal response reflects the acute pain from venom injection and may be brief or followed by focused attention to the affected area.
Pawing or licking at one spot
Persistent attention to a single area—often a paw, the muzzle, or around the lips—tends to begin within moments of the sting. The behaviour reflects localised pain and irritation, and the animal may return to the spot repeatedly even after initial investigation.
Visible swelling at a single point
A raised, firm area of swelling may appear at the sting site within minutes, sometimes with a tiny central puncture mark or reddened skin. The swelling is usually warm to the touch and may expand slightly over the first hour or two.
Holding a limb up or favouring it
If the sting is on a paw or leg, the animal may lift the limb, limp, or avoid placing weight on it. This guarding behaviour reflects both pain and the sensitivity of the swollen tissue.
Vomiting, diarrhoea, pale gums or collapse
In dogs, the gut and liver are the organs most affected in anaphylaxis, so vomiting, diarrhoea that may contain blood, weakness, pale gums and collapse can appear within minutes of a sting, sometimes with little visible swelling. Cats more often show laboured breathing as the leading sign. These patterns reflect effects on circulation and internal organs rather than on the skin.
Later signals
Swelling spreading beyond the sting site
In some cases, swelling extends along the limb or across a larger area of the face or neck over several hours. This more diffuse reaction indicates a broader immune response and may produce noticeable distortion of normal contours.
Increased drooling or difficulty swallowing
Stings inside the mouth or throat can produce swelling that interferes with normal swallowing or causes saliva to pool. The animal may paw at the mouth, gape, or appear uncomfortable when attempting to eat or drink.
Facial swelling or hives elsewhere
Raised welts or patches of swelling may appear on areas away from the sting itself, often on the face, ears, or trunk. These hives suggest a more generalised allergic response rather than a purely local reaction.
Restlessness or altered breathing pattern
Some animals become unusually agitated, unable to settle, or begin breathing more rapidly or with noticeable effort. These patterns can indicate systemic involvement, including effects on circulation or airway tissues.
Click to read about the biological mechanisms
How this is usually investigated
Most bee and wasp sting reactions are diagnosed from the history and physical findings alone—sudden onset of localised swelling, a clear timeline matching outdoor activity, and a visible puncture or area of pain point to the cause without further testing. When the history is less certain, or when swelling is unusually extensive or accompanied by signs affecting breathing, circulation, or other systems, the investigation broadens to assess the severity of the reaction and to exclude other causes of acute swelling or collapse. Laboratory tests and imaging are reserved for cases in which the clinical picture is unclear, the response to initial management is inadequate, or complications are suspected.
Physical examination
Blood pressure measurement
Radiography
Chemistry panel
Complete blood count
Options & trade-offs
Management of bee and wasp sting reactions is shaped by the location of the sting, the extent and distribution of swelling, and the presence or absence of signs affecting breathing, circulation, or other systems. Most reactions are managed with approaches that reduce inflammation and discomfort whilst the body clears the venom over the following hours to days. In more extensive or systemic reactions, additional measures are used to support airway patency, stabilise blood pressure, and prevent progression. The combination of approaches varies between individuals, and what works well for one animal or household may be less practical or necessary for another.
Cold compresses and wound care
Applying a cool, damp cloth or wrapped ice pack to the sting site can reduce local swelling and provide comfort in the first few hours after the sting. If a stinger is visible and accessible, gentle removal with a flat edge—such as a credit card scraped across the skin—can limit further venom release, though by the time most animals are examined the majority of venom has already been delivered. Cleaning the area with mild saline or water removes debris and reduces the risk of secondary infection if the skin is broken.
Trade-offs: Cold compresses are most effective when applied early and may offer little benefit once swelling is well established. Many animals will not tolerate prolonged application, particularly on sensitive areas such as the face or paws, and forcing the issue can increase stress without meaningfully altering the outcome.
Antihistamines
Oral or injectable antihistamines can reduce histamine-mediated swelling, itch, and redness, particularly when given within the first hour or two of the sting. They are commonly used for localised reactions that are uncomfortable but not affecting vital functions, and in some cases they are continued for one to three days to manage ongoing swelling. Different antihistamines vary in their duration of action, sedative effects, and suitability for individual animals.
Trade-offs: Antihistamines are more effective at preventing the development of swelling than reversing it once it is fully established, and they do not address all components of the inflammatory response. Sedation is a common side effect and may be undesirable in animals that need to be monitored closely, whilst some animals show little response even to appropriate doses.
Corticosteroids
Injectable or oral corticosteroids reduce inflammation through multiple pathways and are often used in moderate to severe local reactions or when there is concern about progression to systemic involvement. A single injection may be sufficient for a self-limiting reaction, whilst more prolonged swelling or recurrent signs may be managed with a short tapering course of tablets. Corticosteroids can also be used alongside other treatments in animals showing early systemic signs.
Trade-offs: Corticosteroids carry a risk of increased thirst, urination, and appetite, and in animals with underlying conditions such as diabetes or Cushing's disease they may complicate management. They do not provide immediate relief in the same way that adrenaline does in a true anaphylactic reaction, and their benefit is greatest when inflammation rather than acute vascular collapse is the primary concern.
Adrenaline and intravenous fluid support
In rare cases where systemic signs such as difficulty breathing, collapse, or profound weakness develop rapidly, adrenaline is given by injection to reverse widespread vasodilation, support blood pressure, and relax constricted airways. Intravenous fluids are often administered concurrently to restore circulating volume and maintain organ perfusion whilst the reaction is brought under control. These interventions are typically delivered in a clinical setting with close monitoring of heart rate, respiratory effort, and blood pressure.
Trade-offs: Adrenaline acts quickly but has a short duration of effect, and repeated doses or a continuous infusion may be needed if signs recur. It can cause transient increases in heart rate and anxiety, and it is reserved for situations in which the potential benefit outweighs these effects. Intravenous fluid therapy requires venous access and monitoring, and it is not appropriate for all animals or all severities of reaction.
Observation and supportive care
In mild, localised reactions, observation alone may be appropriate, allowing the inflammatory response to resolve over one to three days without pharmaceutical intervention. This approach is often chosen when the swelling is minor, the animal is comfortable, and there are no signs of progression. Owners monitor for changes in the extent of swelling, breathing pattern, behaviour, and appetite, and further intervention is introduced if the reaction worsens or fails to improve as expected.
Trade-offs: Observation requires confidence in recognising deterioration and access to veterinary advice if the situation changes. It may not suit animals with stings in high-risk locations such as the mouth or throat, where even modest swelling can compromise the airway, and it offers no active reduction in discomfort for animals that are notably painful or distressed.
Common misconceptions
"A dog or cat that has been stung once will always have a more severe reaction the next time."
Whilst sensitisation can occur with repeated stings, leading to a more vigorous immune response on subsequent exposure, many animals are stung multiple times over their lives without escalating reactions. The severity of any given reaction depends on the dose and location of venom, the individual's immune status at the time, and chance variation in the inflammatory cascade, and prior sting history does not reliably predict the severity of a future reaction. A mild reaction one time does not rule out a severe reaction the next, and an animal that has had a systemic reaction remains at risk of another.
"Bee stings are always more dangerous than wasp stings because bees leave their stinger behind."
The presence of a stinger does allow continued venom delivery for a short period if it is not removed, but the majority of venom is injected in the first few seconds, and the clinical severity of the reaction is determined more by the location of the sting, the volume of venom, and the individual's immune response than by the insect species. Wasps can sting repeatedly without losing their stinger, which can result in multiple venom doses if the animal continues to interact with the insect, but a single wasp sting is not inherently less serious than a single bee sting.
"Applying vinegar or baking soda to a sting neutralises the venom and prevents swelling."
Venom is injected beneath the skin surface, where topical applications cannot reach the molecules driving the inflammatory response. Whilst some venoms are acidic and others alkaline, the reaction in the tissue depends on immune cell activation rather than simple pH, and there is no evidence that surface treatment with household substances alters the course or severity of swelling in dogs or cats.
Related conditions
Flea Allergy Dermatitis
Flea allergy dermatitis shares a mechanism with sting reactions: in both conditions, proteins from an insect (flea saliva or venom) trigger a localised or more widespread immune response, producing inflammation, swelling, and discomfort at or beyond the site of contact. An animal with a history of flea allergy may have a heightened tendency toward other hypersensitivity reactions.
Atopic Dermatitis in Dogs
Dogs with atopic dermatitis often have an immune system primed to over-react to environmental triggers, and this background hypersensitivity can influence how the body responds to insect venom. Both conditions involve mast cell activation and the release of inflammatory mediators that drive swelling and itch.
Acute Moist Dermatitis (Hot Spots)
Acute moist dermatitis can develop when a dog repeatedly licks or scratches at a sting site, introducing bacteria to skin already damaged by inflammation. The rapid onset and self-traumatising cycle are shared features, though the triggers differ.
Anticoagulant Rodenticide Toxicity
In rare cases, systemic reactions to stings can cause clotting abnormalities or vascular injury that lead to bruising or bleeding, a pattern that may resemble the effects of anticoagulant toxicity. Both can present with unexpected haemorrhage, though the underlying mechanisms—immune-mediated versus direct interference with clotting factors—are distinct.
Aspiration Pneumonia
Swelling from a sting inside the mouth or throat can sometimes cause difficulty swallowing or changes in the normal protective reflexes, and in rare instances material may enter the airways rather than the oesophagus. This mechanism of aspiration overlaps with other causes that disrupt the coordination of breathing and swallowing.
Snake Envenomation (Adder Bite)
An adder bite can produce sudden, painful swelling of the face or a limb that looks much like a sting reaction, and both are seen in the warmer months. The two small puncture marks of a bite are often hidden by fur, and adder venom can go on to affect clotting, blood pressure, heart rhythm and the kidneys over the following hours, so the cause of a sudden swelling is not always clear from its appearance at home.
Acute Kidney Injury
Kidney injury has been reported in dogs after multiple stings and after sting-associated anaphylaxis, arising from low blood pressure, pigments released from damaged red blood cells and muscle, and direct effects of venom. It can become apparent over the days after the sting, when the visible swelling may already be improving.
Immune-Mediated Haemolytic Anaemia (IMHA)
Destruction of red blood cells has been reported in dogs after multiple bee stings and, occasionally, after a single wasp sting, through direct effects of venom components and immune-mediated mechanisms. It can appear within hours of the sting or be delayed for several days, with pale gums, weakness or dark urine.
Swelling that spreads beyond the sting site within an hour, drooling or difficulty swallowing after a sting inside the mouth, hives appearing away from the sting site, or restlessness with a fast or laboured breathing pattern reflect a different, faster-moving picture than an isolated local reaction. Systemic reactions usually begin within about half an hour of the sting and can worsen over minutes, and a faster onset tends to go with a more severe reaction. Gut and breathing signs can also be the leading indication of anaphylaxis, sometimes with little visible swelling, and swelling at the back of the mouth or in the throat cannot be seen or gauged at home. How a reaction looks in its first minutes does not show where it will be an hour later. The fast-moving form can progress to airway obstruction, collapse or death. For that reason, mouth or throat swelling, a change in breathing, vomiting or collapse after a sting carry their weight while they are happening, not once the reaction has settled. Antihistamines act too slowly to reverse a reaction that is affecting breathing or circulation, so having one in the house does not change what those signs mean. For animals that have had a systemic reaction or unusually severe local swelling, revisiting the event at a later appointment can be a chance to discuss precautions, such as adjusting outdoor routines during peak insect activity.
Last reviewed: 13 September 2026 · Dr Alastair Greenway MRCVS