Coloured scanning electron micrograph (SEM) Pet dander: dog hair, cat hair and dead skin. Dog and cats produce human allergens. Pet dander is the material shed from the body of various animals (commonly cats and dogs). It may contain scales of dried skin and hair. Substances within the dander can cause human allergies (allergic reaction).There are 5 known allergens produced by cats, all which cause allergic reactions. Female cats produce a lower level of allergens than males. An allergic reaction is a histamine reaction that is usually characterized by coughing, wheezing, itching, nasal congestion, rash, watering eyes, and sneezing. Magnification: x80 when shortest axis printed at 25 millimetres.