Why weeks of licking led to this rash
The raw egg white habit your cat has developed is causing a gradual nutrient lockout. Each lick introduces avidin, a protein that tightly binds biotin — a vitamin crucial for skin health and coat condition. Unlike a one-time exposure, this slow depletion means symptoms only surface after the body's reserves are drained. For a 4 kg cat, even small daily amounts add up over weeks.
What you're seeing now — the rash, flaky skin, or dull fur — suggests the deficiency has reached a tipping point. Cats don't show immediate reactions to raw egg whites because the damage is cumulative. The first visible changes usually appear between 3-8 weeks of regular exposure, depending on how much egg white they ingest and their individual biotin stores.
How this differs from a single egg white incident
If your cat had eaten a whole raw egg white once, the avidin would pass through without causing lasting harm. Chronic exposure is the real concern because the binding happens repeatedly, preventing biotin absorption over time. A 4 kg cat licking plates clean daily is getting enough avidin to overwhelm their biotin recycling system.
Unlike poisoning cases where symptoms hit fast, deficiency signs creep in subtly. You might have noticed increased shedding or slight dandruff before the rash appeared. This slow progression makes it easy to miss the connection until more obvious skin problems develop.
What to expect in the coming days
Now that symptoms are visible, the rash may worsen for another week even if you stop all egg white exposure today. The body needs time to rebuild biotin levels. Without intervention, the next stages often involve hair loss around the eyes and mouth, or crusty lesions on the paws.
Monitor for excessive scratching — the dry skin can become itchy, leading to secondary infections from broken skin. Check between the toes and under the chin for red, irritated patches. These areas are prone to moisture buildup and bacterial growth when the skin barrier weakens.
Why your cat's weight matters here
A 4 kg cat has less biotin reserve than a larger animal, making them vulnerable to quicker depletion. Smaller bodies also metabolize nutrients faster, so the deficiency impacts them sooner. What might take months to affect a 7 kg cat could show up in weeks for yours.
The good news is that lighter cats often rebound faster once the source is removed and proper nutrition resumes. Their smaller size means therapeutic doses of biotin (from vet-approved sources) can restore balance more quickly than in heavier animals. However, the skin may take 2-4 weeks to fully heal.
The step-by-step response, from the first minute to the vet visit, is in our Raw Egg Whites (Avidin) Poisoning emergency guide.