A low-allergen shortlist is built by ranking breeds on coat type, shedding pattern and the proteins carried in saliva, urine and dander, not by looking for a breed that produces no allergens. No breed is allergen-free, and the proteins that trigger symptoms are small enough to travel on hair and skin flakes regardless of coat length. The same pre-adoption file should also record whether the dog carries an MDR1 mutation, because that gene changes how the animal handles several common drugs, including ivermectin.
How is a low-allergen shortlist built?
The starting point is the protein, not the dog. Can f 1 is the main dog allergen for most people, and it is found in saliva, urine and dander. A dog deposits it on its coat when it licks itself, and the protein then moves into the air on skin flakes and hair. Coat type and shedding pattern change how much of that material stays in the home, which is why some breeds are described as lower-allergen rather than safe.
A practical shortlist uses three filters.
Coat. A curly or continuously growing coat holds shed hair instead of releasing it into the room. Breeds in this group include the poodle, the bichon maltais, the bichon frise, the yorkshire, the shih tzu and the bolonka. A short, single coat that sheds heavily releases more dander into the environment.
Shedding. Shedding is the delivery system for dander. A breed that sheds little leaves less material on sofas, bedding and floors, which lowers the dose a person inhales. This is a relative difference, not an absolute one.
Saliva and grooming. A dog that licks its coat spreads saliva-borne protein across its body. Frequent grooming moves that protein onto the skin and into the air. A person who reacts strongly to Can f 1 may still react to a low-shedding breed, because the protein is present in every dog.
A shortlist is therefore a ranked set of candidates, not a guarantee. The ranking should be checked against the individual, not the breed alone. Spending time with a specific dog before adoption is the only way to test a real reaction, and it is the step that many households skip.
For households working through the same decision in French, choosing a dog when allergic covers the protein mechanism, a six-criteria breed comparison and the practical steps before and after adoption. The useful part for a clinical file is the same: the breed list is a filter, and the individual dog is the test.
Why add a drug-sensitivity check to the same file?
The pre-adoption file usually covers housing, budget, grooming and veterinary care. Drug sensitivity belongs in that same file because it is a property of the individual dog, and it can be checked before the dog comes home.
MDR1, also called ABCB1, codes for a pump that moves drugs out of the brain. A dog with a non-functional copy of this gene lets certain drugs accumulate in the central nervous system at doses that other dogs tolerate. Ivermectin is the classic example, and the resulting syndrome is well described in veterinary toxicology. The same pump handles other compounds, so the list of drugs to avoid is longer than ivermectin alone.
This matters for a new dog because the first year of ownership involves several routine decisions: heartworm prevention, deworming, flea control and any sedation or anesthesia. A dog with an MDR1 mutation needs those decisions made differently. Knowing the genotype before adoption turns a series of rushed choices into a plan.
The test is a DNA test, and it can be ordered through a veterinarian or a laboratory. The result is a genotype: clear, carrier or affected. A carrier has one copy and is usually clinically normal, but can pass the mutation to offspring. An affected dog has two copies and is at risk from the drugs in question.
Breeds with a higher frequency of the mutation include collies, Australian shepherds, Shetland sheepdogs, old English sheepdogs and several other herding lines. A mixed-breed dog can carry it too, which is why the test is worth doing when the ancestry is uncertain. The result goes in the same folder as the allergy notes, the vaccination record and the microchip number.
What should be settled before the dog comes home?
Four items should be resolved before the dog arrives.
First, the household reaction. Decide who will spend time with the dog, for how long, and in what room. A short visit in a neutral space is a starting point, not a final answer. Some reactions build over hours, so a longer visit in the home is more informative.
Second, the sleeping arrangement. A dog that sleeps on the bed deposits dander and saliva protein directly into the bedding. A dog that sleeps in a separate room or a crate keeps that load lower. This is a decision to make before adoption, not after the first bad night.
Third, the cleaning routine. Washable covers, frequent vacuuming with a filter, and a washable dog bed reduce the amount of protein in the air. A dog that is bathed and brushed on a schedule carries less loose material. These steps are more effective when they are planned in advance.
Fourth, the drug plan. If the dog is an MDR1 carrier or affected, the veterinarian needs to know before the first heartworm dose. Preventive products differ in their active ingredients, and some are safer than others for a sensitive dog. The plan should name the products that are acceptable and the ones that are not.
A shortlist, a genotype and a cleaning routine are three separate documents, but they belong in one file. The file is what makes the first month manageable.
What a shortlist cannot tell you
A breed list cannot predict an individual reaction. Two dogs of the same breed can carry different amounts of Can f 1, and a person's sensitivity varies with exposure, medication and time of year. A low-shedding breed in a home with poor ventilation can produce more airborne protein than a shedding breed in a home with good filtration.
A breed list also cannot predict drug sensitivity. MDR1 status is inherited, not linked to coat type, so a low-allergen breed can still be affected. The two questions are independent, and both belong in the same pre-adoption file.
The practical conclusion is that the shortlist narrows the search, the individual dog tests the reaction, and the genotype sets the drug rules. None of the three replaces the others.
Where the evidence comes from
The MDR1 mutation and its drug list are documented by the Veterinary Clinical Pharmacology Laboratory at Washington State University, which maintains a reference page for the mutation and the drugs involved. That page is the appropriate source for the genotype and the drug categories. For the allergy side, the protein mechanism and the breed comparison are covered in the French-language guide cited above. A veterinarian can combine both lines of information into a single plan for a specific dog.
The figures and rules in this file come from the WSU MDR1 programme, which maintains the reference laboratory testing and the published mutation data behind the drug-sensitivity list. Its pages set out which breeds and crosses carry the defect, which drugs carry risk, and what a test result does and does not establish. Owners and veterinarians can use that material to confirm each entry before a shortlist is finalised, and to check any claim that a breeder, a shelter or a website makes about a dog's MDR1 status.