Rat allergy
Allergy to rat proteins.
About rat allergy
Rat allergy is an IgE-mediated reaction to proteins present mainly in rat urine, along with dander (skin flakes) and saliva, rather than the fur. A major rat allergen, Rat n 1, is a urinary protein, so soiled bedding and litter are significant sources of exposure. It affects people who keep pet rats but is a particularly well-documented occupational allergy among laboratory animal workers, and wild rats in buildings can raise indoor allergen levels too. The particles readily become airborne and are sticky, settling on clothing, cages and surfaces where they can persist and spread beyond the immediate area.
Symptoms generally appear within minutes to hours of contact and include sneezing, nasal congestion and itchy, watering eyes. In susceptible people, handling rats or disturbing their bedding can provoke asthma symptoms or worsen eczema. Because the allergen is airborne and spreads onto surfaces, reactions can occur without touching an animal, for instance in a poorly cleaned animal facility. These reactions are usually uncomfortable rather than dangerous.
Diagnosis is made with a skin-prick or specific-IgE blood test alongside your history and occupation where relevant. Avoiding rats is most effective; where they must be handled, reduction measures help, such as good ventilation, dust control, gloves and a mask, changing out of work clothes and washing hands afterwards. Medicines relieve symptoms, and immunotherapy is considered in selected cases. See your GP, particularly if you develop any breathing problems.
Common triggers
- Rat and products containing it
Symptoms
- Sneezing and a runny or blocked nose
- Itchy, watery eyes
- Skin redness where the animal licked or touched
- Coughing or wheezing
- Worsening of asthma
Avoidance & management
- Limit contact with the animal
- Keep pets out of bedrooms
- Wash hands and clothes after contact
- Use air filtration and vacuum often
- Take prescribed antihistamines
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.