Ammonia
Ammonia is a colorless, strong-smelling chemical compound with the formula NH₃, which can be highly toxic to humans and animals in concentrated form. At room temperature, ammonia exists as a gas and dissolves easily in water. Many household cleaners contain ammonia in various concentrations, with so-called “all-purpose cleaners” potentially being up to 25% ammonia solutions. These highly concentrated solutions are corrosive and toxic.
The toxicity of ammonia is based on its strongly basic properties (pH value of about 11–12 in concentrated solution), which can lead to chemical burns, as well as its ability to interfere with metabolism. The mucous membranes of the respiratory tract, the eyes, and the digestive tract in case of oral ingestion are particularly at risk. Ammonia has a strong corrosive effect on moist body surfaces and can cause profound tissue damage.
Dogs and cats are particularly sensitive to ammonia poisoning due to their body size and physiological characteristics. Cats often show more severe symptoms than dogs with comparable exposure, due to their lower body weight and specific metabolic properties.
The most important facts at a glance
The prognosis of ammonia poisoning largely depends on the severity of exposure, the concentration of ammonia, the time until therapy begins, and the affected organ system.
In mild poisonings with predominantly local irritation symptoms, the prognosis is generally good. Most animals recover completely within a few days if adequate therapy is initiated.
For moderate poisonings involving the lower respiratory tract, the prognosis is guarded. Healing can take weeks, and there is a risk of secondary infections or the development of chronic bronchitis.
Severe poisonings involving pulmonary edema, respiratory failure, or extensive caustic injuries to the digestive tract have an unfavorable prognosis. Even if the acute phase is survived, long-term consequences such as lung scarring with chronic impairment of lung function, strictures in the digestive tract, or permanent eye damage may persist.
Aftercare includes:
- Regular follow-up examinations to assess healing
- Repeated chest X-rays for severe respiratory symptoms
- Medication adjustment based on recovery progress
- Respiratory physiotherapy if needed
- Dietary measures for caustic injuries to the digestive tract
- Long-term monitoring of lung function in severe cases
To prevent further incidents, pet owners should be educated about the safe storage and use of ammonia-containing products. Alternative, more pet-friendly cleaning agents can be recommended.
Causes, development and progression
“All-purpose cleaner”, for example, is a 25% ammonia solution and is highly toxic and corrosive.
Ammonia poisoning in pets can occur in various ways. The most common routes of exposure are:
Inhalation of ammonia fumes is the most common route of exposure. This can happen during cleaning with ammonia-containing products in poorly ventilated areas. Situations where ammonia is mixed with chlorine-containing cleaners are particularly dangerous, as highly toxic chloramines can be formed.
Oral ingestion is less common, as the pungent odor usually deters animals. However, dogs drinking from toilet bowls may ingest ammonia residues if toilet cleaners have been used previously. Licking paws after contact with cleaned surfaces can also lead to oral ingestion.
Skin contact with concentrated ammonia solutions can cause chemical burns. Paw pads are particularly sensitive if animals walk over freshly cleaned, still damp surfaces.
Eye contact can occur from splashes during cleaning or if animals touch their eyes with contaminated paws, leading to severe irritation or even chemical burns.
In addition to household cleaners, there are other often-overlooked sources of ammonia:
- Insufficiently cleaned litter boxes, where ammonia forms due to bacterial decomposition of urea
- Agricultural sources such as slurry and certain fertilizers
- Poorly maintained aquariums, where ammonia can accumulate through biological processes
- Industrial sources in the vicinity of residential areas
The pungent odor makes it unattractive for animals, so drinking is unlikely.
However, dogs accustomed to drinking from the toilet bowl could also ingest ammonia residues orally.
Licking paws after contact and inhaling fumes are the main sources of unintentional ammonia exposure.
Mechanism of action
The toxic effect results from both local action and systemic effects after absorption.
Ammonia has a strong corrosive effect locally on moist body surfaces such as eyes, skin, lungs, and the mucous membranes of the oral cavity and gastrointestinal tract.
This effect is independent of whether ammonia was inhaled or ingested orally.
After absorption, ammonia affects one of the body’s most important metabolic processes, the citric acid cycle, which is responsible for the metabolism of carbohydrates, fats, and proteins.
Metabolic processes change, leading to increased acid (lactate) production, resulting in acidosis (lactic acidosis).
This causes cell damage and damage to the CNS.
Symptoms of intoxication
Inhaled in low concentrations, ammonia causes
- Burning in the eyes
- Tearing
- Irritation of the nasal mucous membranes
- Sneezing
- Coughing
- Throat irritation
In high concentrations, even a few breaths can lead to severe respiratory symptoms.
- severe irritation
- Laryngospasm (spasm of the larynx)
- Difficulty breathing
- Inflammation to chemical burns
- toxic pulmonary edema
- respiratory insufficiency
- Hypoxia
- acute lung failure
- Unconsciousness
With oral ingestion
- Vomiting, sometimes bloody
- severe abdominal pain
Supplements
The symptoms of ammonia poisoning vary depending on the route of exposure, concentration, and duration of exposure. Generally, a distinction is made between symptoms after inhalation and after oral ingestion.
When inhaling low ammonia concentrations, affected animals show:
- Burning in the eyes with increased tear production
- Irritation of the nasal mucous membranes with sneezing and nasal discharge
- Coughing and retching
- Restlessness and behavioral changes
- Increased respiratory rate
- Drooling
With inhalation of high ammonia concentrations or prolonged exposure, more severe symptoms may occur:
- Severe shortness of breath with wheezing or rattling breath sounds
- Laryngospasm (laryngeal spasm)
- Cyanosis (bluish discoloration of the mucous membranes)
- Development of toxic pulmonary edema with frothy nasal discharge
- Respiratory insufficiency
- Hypoxia with impaired consciousness leading to unconsciousness
- Seizures due to lack of oxygen in the brain
With oral ingestion of ammonia, the following symptoms become prominent:
- Excessive salivation
- Chemical burns of the oral mucous membrane with redness, swelling, and ulcerations
- Vomiting, sometimes with blood
- Severe abdominal pain, recognizable by a tense abdominal wall and expressions of pain
- Diarrhea, possibly with blood
- Difficulty swallowing
- Dehydration
In case of skin contact, local chemical burns with redness, swelling, and blistering may occur. Eye contact leads to severe conjunctivitis, corneal damage, and intense tearing.
Diagnosis
The diagnosis of ammonia poisoning is primarily based on the anamnesis and the clinical picture. Crucial information includes possible contact with ammonia-containing substances and the characteristic symptoms.
During the clinical examination, the veterinarian pays particular attention to:
- Respiratory rate and pattern
- Auscultation of the lungs to detect crackles or dullness
- Mucous membrane color to assess oxygen supply
- Examination of the oral cavity for chemical burns if oral ingestion is suspected
- Assessment of hydration status
To confirm the diagnosis and assess the severity, the following diagnostic measures may be useful:
Imaging procedures:
- Thoracic X-rays to assess lung parenchyma and detect pulmonary edema
- In severe cases, a computed tomography (CT) scan can be helpful for detailed visualization of lung changes
Laboratory diagnostics:
- Blood gas analysis to assess respiratory function and acid-base balance
- Blood count to detect inflammatory reactions
- Clinical-chemical examinations to assess organ functions, especially liver and kidneys
- In case of oral ingestion, determination of electrolytes and kidney values
Endoscopic examinations:
- In case of suspected severe chemical burns of the upper digestive tract, an endoscopic examination of the esophagus, stomach, and duodenum may be indicated
- Bronchoscopy to assess the airways in severe respiratory symptoms
The differential diagnosis includes other intoxications with corrosive substances, acute bronchitis, pneumonia, bronchial asthma, foreign body aspiration, and allergic reactions.
Therapeutic principles
There is no antidote.
In severe ammonia poisoning, life-saving emergency resuscitation measures may be necessary.
This means:
- Check breathing, if absent →
- Chest compressions (30x)
- Ventilation (2x)
Immediate measures include decontamination. Affected body parts (eyes, fur, paws) should be thoroughly cleaned. Eyes should be flushed for at least 15 minutes if possible.
For decontamination of fur or paws, generous and prolonged flushing with lukewarm water, or showering/bathing the animals, should be performed.
When bathing animals, remember to change the water.
If ammonia has been swallowed, vomiting should not be induced; instead, dilution of the ammonia in the stomach should be attempted by administering warm water. This should be followed by repeated gastric lavage.
Symptomatic therapy then follows.
The focus is on lung function and thus the body’s oxygen supply.
Often, oxygen enrichment of the breathing air during spontaneous breathing or mechanical ventilation is necessary.
Special attention is paid to water, electrolyte, and acid-base balance, as well as the treatment of pulmonary edema.
Supplements
The treatment of ammonia poisoning depends on the type of exposure, the severity of symptoms, and the time of veterinary presentation. There is no specific antidote for ammonia, so symptomatic therapy is paramount.
Immediate measures and decontamination:
In case of skin contact, thorough flushing with lukewarm water for at least 15–20 minutes should be performed. Affected animals can be showered or bathed, with the water changed multiple times. In case of eye contact, extensive flushing with physiological saline solution or water for at least 15–20 minutes is required.
Vomiting should not be induced after oral intake, as this would lead to re-exposure of the esophagus to the corrosive ammonia. Instead, dilution should be attempted by carefully administering water. In the hospital, gastric lavage under general anesthesia may be considered.
Airway Management:
- Oxygen therapy for the treatment of hypoxia
- In severe respiratory distress, intubation and mechanical ventilation may be necessary
- Bronchodilators to widen the airways
- Inhalation therapy with humidified air to aid mucous membrane clearance
Medical Therapy:
- Corticosteroids to reduce inflammatory response in the airways (controversial, as they can delay healing)
- Antibiotics in case of suspected secondary infections
- Analgesics for pain relief
- Proton pump inhibitors or H₂ receptor antagonists for chemical burns of the digestive tract
- Infusion therapy to stabilize circulation and correct electrolyte and acid-base imbalances
In severe cases, intensive care monitoring with regular checks of blood gases, acid-base balance, and vital parameters may be required.
Prognosis & follow-up care
The prognosis of ammonia poisoning largely depends on the severity of exposure, the concentration of ammonia, the time until therapy begins, and the affected organ system.
In mild poisonings with predominantly local irritation symptoms, the prognosis is generally good. Most animals recover completely within a few days if adequate therapy is initiated.
In moderate poisonings involving the lower respiratory tract, the prognosis should be cautious. Healing can take weeks, and there is a risk of secondary infections or the development of chronic bronchitis.
Severe poisonings with pulmonary edema, respiratory failure, or extensive chemical burns of the digestive tract have an unfavorable prognosis. Even if the acute phase is survived, long-term consequences such as scarring in the lungs with chronic impairment of lung function, strictures in the digestive tract, or permanent eye damage may persist.
Aftercare includes:
- Regular follow-up examinations to assess healing
- Repeated chest X-rays for severe respiratory symptoms
- Adjustment of medication depending on the course of healing
- Airway physiotherapy if needed
- Dietary measures for chemical burns of the digestive tract
- Long-term monitoring of lung function in severe cases
To prevent further incidents, pet owners should be educated about the safe storage and use of ammonia-containing products. Alternative, more pet-friendly cleaning agents can be recommended.
Research outlook
Current research in the field of ammonia poisoning in small animals focuses on several promising areas:
New therapeutic approaches for treating lung burns are being investigated, including the use of surfactant preparations to improve lung function in toxic pulmonary edema. These substances could reduce surface tension in the alveoli and thus improve gas exchange.
In the field of regenerative medicine, the application of stem cell therapies to support tissue regeneration after severe caustic injuries is being researched. Initial studies show promising results in the healing of mucosal damage.
Improved biomarkers for the early detection of organ damage could enable more precise prognoses in the future. Specific inflammatory mediators and cell damage markers are being investigated for their significance in ammonia poisonings.
The development of inhalation therapies with special active ingredient combinations could optimize the local treatment of airway damage. Formulations with mucolytic, anti-inflammatory, and epithelial-regenerating properties are a focus.
Prevention is also supported by research into safer household cleaners. Manufacturers are working on products with reduced ammonia content while maintaining cleaning performance, as well as child-safe and pet-safe packaging.
The long-term consequences of ammonia poisoning are being systematically recorded in follow-up studies to develop better rehabilitation protocols and to detect and treat chronic complications early.
Frequently asked questions (FAQs)
- How do I identify ammonia-containing cleaning products?
Ammonia-containing products usually have a characteristic, pungent odor. Labels may include indications such as “contains ammonia”, “ammonium hydroxide”, or “spirit of sal ammoniac”. Pay attention to hazard symbols and warnings on the packaging. - How long should I observe my pet after ammonia poisoning?
After mild poisoning, you should observe your pet for at least 24–48 hours, as pulmonary edema can develop with a delay. In severe poisonings, veterinary monitoring for several days is necessary. - What ammonia-free alternatives are there for household cleaning?
Vinegar, citric acid, baking soda, or special eco-friendly cleaners without ammonia are good alternatives. These are less dangerous for pets and often just as effective. - Can a single exposure to ammonia fumes cause permanent damage?
Yes, even a single exposure to high concentrations can lead to permanent lung damage. Situations in enclosed, poorly ventilated rooms are particularly dangerous. - Are cats or dogs more sensitive to ammonia?
Cats are often more sensitive to ammonia fumes due to their specific airway anatomy and lower body weight. Additionally, they spend more time grooming, which allows them to orally ingest substances from their fur. - How can I prevent my pet from coming into contact with ammonia?
Store cleaning products in locked cabinets, ventilate thoroughly during and after cleaning, keep animals in other rooms during cleaning, and rinse cleaned surfaces well. - Can ammonia concentration in litter boxes become dangerous?
Yes, with insufficient cleaning, ammonia can form in litter boxes due to bacterial decomposition of urea. This can lead to chronic respiratory irritation. Regular cleaning and good ventilation are important. - What first aid measures can I take if ammonia poisoning is suspected?
Immediately take the animal to fresh air, rinse affected body parts with plenty of lukewarm water, and contact your veterinarian immediately. Do not attempt to induce vomiting. - Are there long-term consequences after recovering from ammonia poisoning?
After severe poisonings, chronic bronchitis, lung scarring with impaired lung function, strictures in the digestive tract, or corneal damage may remain. - How long does full recovery take after ammonia poisoning?
In mild cases, recovery can occur within a few days. In moderate to severe poisonings, the healing process can take weeks to months, and regular veterinary check-ups are required.
Literature
- Dodd, K. T., & Gross, D. R. (1980). Ammonia inhalation toxicity in cats: a study of acute and chronic respiratory dysfunction. Archives of Environmental Health: An International Journal, 35(1), 6-14.
- Dörfelt, R., & Richter, P. (2018). Poisoning with Household Cleaners in Cats. Kleintierpraxis, (4), 176-186.
- Löwe, G, Löwe, O: Poisoning in Dogs and Cats. 2nd Edition, Kynos Verlag, 2021. 208 pp.
- Bates, N. and Edwards, N. (2019). Toxicology of common household hazards. In Practice, 41(10), 385-392. https://doi.org/10.1136/inp.l6742
- Lee, J. A. (2021). Decontamination and treatment of common household toxicoses in dogs and cats. Veterinary Clinics of North America: Small Animal Practice, 51(6), 1299-1315. https://doi.org/10.1016/j.cvsm.2021.06.006
- Mazzaferro, E. M. (2020). Small Animal Toxicological Emergencies. In Silverstein, D. C. & Hopper, K. (Eds.), Small Animal Critical Care Medicine (3rd ed., pp. 834-839). Elsevier.
- Peterson, M. E. and Talcott, P. A. (2022). Small Animal Toxicology (4th ed.). Elsevier Health Sciences.
- Wismer, T. A. and Means, C. (2018). Toxicology of Household Cleaning Products and Disinfectants. Veterinary Clinics of North America: Small Animal Practice, 48(6), 1019-1029. https://doi.org/10.1016/j.cvsm.2018.06.007