Rat 1,5year old. BW 600g. Sudden pruritus and skin lesions. Owner's other (young

小朱朱

Rat 1,5year old. BW 600g. Sudden pruritus and skin lesions. Owner's other (younger) rats itch but have no skin lesions.
Skin scrape and squeeze: Found two somewhat rounded/rectangular  egg-looking structures but that's it.
Treated all rats in contact with oral ivermectin injectable 0,4mg/kg pluss affected rat with antihistamin.
Anyone know any skin parasite in rats that produce rounded rectangularish eggs ?