DEAR PAW’S CORNER: My cat “Starlight” has terrible skin allergies, and I haven’t been able to pinpoint the cause. She does not have fleas -- I give her a monthly topical treatment and keep the house clean. She’s an indoor cat, so environmental allergies may not be a problem, according to my veterinarian. Could she have a food allergy? -- Blake W. in Syracuse, New York DEAR BLAKE: A food allergy is…