Case study shows cat bites may lead to allergy, should be included in medical history
The girl, who was seven years old, was in the home of a friend in the month of November 2021. The friend owned one of their cats who bit her on the palm of her hands. While the girl had visited the house before, this was the only time the cat ever bit her.
In the next few days, the girl developed an erythematosus spot with no bleeding. A couple of months after, when she went back to this home her eyes were red with conjunctival irritation with sneezing, breathing issues and coughing within 30-60 minutes of arriving. One month later she had another asthma attack at a different house that had the cat.
A checkup for allergies in March 2022 contained an positive skin prick test of cat’s dander (8 millimeters) as well as Positive specific IgE tests on cat excrement (9.76 KU/L) and rFel d1 (10.9 KU/L). Specific IgE tests for Fel d2 and rFel d 4 were not positive. The total IgE level was 129.8 IIU/mL.
At the age of 18 months old, the child started suffering from frequently respiratory tract infections accompanied by nasal mucous secretions, rhinitis and cough. There was no evidence of atopic dermatitis, or food allergies. A previous SPT test for cat allergens, which included inhalants performed at 2 years and 10 months old, was not positive. There were no pets at home.
In September the girl started taking 50 mg of fluticasone every day as a long-term treatment for asthma and to prevent the occurrence of exacerbations from her respiratory tract infections in the upper part of her body. SPT results in September 2021 was positive for grasses (5 millimeters) and olive tree (5 5 mm), Dermatophagoides farinae (6 mm) and Dermatophagoides Pteronissinus (6 millimeters) however not positive for the cat’s extract.
Fel D1, that the researchers of the case study referred to as the cat’s primary allergen is produced primarily through saliva of the cat and sebaceous glands. Cat bites can cause anaphylaxis, as per the study’s authors, suggesting that a bite may contain enough allergens to cause symptoms and trigger sensitization.
Finding a novel route to cat allergy is unlikely following years of research in the journal of the authors however, patient histories generally do not contain information about cat bites. The authors recommended, in turn that doctors include specific questions regarding cat bites in their medical reports.
Additionally, the authors suggested future research on the consequences of tissue damage that is caused by cat bites which may provide information on the possibility of higher risk of susceptibility to cats’ dander owing to skin barrier deficiencies.