The Kennel Club is not a veterinary organisation and is unable to provide general or case specific veterinary advice. They just use them differently. Normal anal gland fluid ranges from yellow to tan in colour and is watery in consistency. In some dogs, this needs to be done every week or two. Comfortis and Trifexis are good ones.
Not present in humans, they are paired sacs located precisely just below the surface of the skin between the external and internal sphincter muscles, employed by nature to produce a particularly thick, foul smelling, oily liquid secreted by glandular tissue for identification and territory marking.
Anal Glands (Sacs): Impactions, Infections & Abscesses in Dogs
Your pet sounds like he has a skin allergy and these are tough. The most common bacterial isolates from anal gland infection are E. These sacs are found in all carnivoraincluding bears  sea otters  and kinkajous. Skunks discharge the secretion from these glands as a form of defense, while dogs use it primarily for territorial marking or as a form of communication. As the opossum mimics death, the glands secrete a foul-smelling liquid, suggesting the opossum is rotting. Ringworm also damages the skin layer in a slightly different way, but the hair follicles are also affected Other signs include licking or biting around their anal area, chasing their tail, sitting uncomfortably, or even licking paws - both front and back - in sheer frustration.