Feline acne is a skin condition of cats that is probably more common than is generally appreciated, as most cases are mild and pass unnoticed. However, more severe cases are obvious, unsightly, and may respond slowly to treatment.
Sebaceous glands in the skin and scent marking
Two main types of glands are found in the skin of the cat – sweat glands and sebaceous glands. Most of the sebaceous glands are associated with hair follicles and produce an important oily secretion – sebum – which waterproofs the hairs and maintains the suppleness of the skin. In addition, a collection of much larger sebaceous glands are found on the chin, the lips, the dorsal (top) surface of the base of the tail and also the eyelids, prepuce and scrotum. The collection of glands under the skin in the chin area is sometimes referred to as the 'submental organ' and the glands around the base of the tail are known as the 'supracaudal organ'.
The special oily secretion of these larger sebaceous glands has an important role in scent marking, and cats will repeatedly rub their chin, lips, temporal area and base of tail over certain objects. In time the secretions build up on favourite marking objects and may be seen as black-brown, greasy patches. You may also notice that they are 'marked' by your cat on returning home (by the cat rubbing against you). Cats will also often mark certain objects at feeding time.
Stud tail and chin acne
Overactivity of the submental organ (sebaceous gland on the chin) is a relatively common finding and termed 'chin acne'. This is seen as excessive greasiness of the overlying fur and skin. This is particularly noticeable on the chin of white or pale coloured cats and appears as a yellow, greasy discolouration. There may also be flecks of black, greasy material on the chin which may be mistaken for flea dirt.
Overactivity of the glands at the base of the tail is often known as 'stud tail' and can produce a similar appearance in this region. Although stud tail is seen most commonly in entire males (where testosterone presumably influences its development), it can occasionally be seen in neutered males and in females. The overactivity of the sebaceous glands predisposes to development of feline acne. The hair follicles produce excessive sebaceous material and possibly also excessive keratin (the major protein in skin and hair). The associated hair follicles become plugged with black sebaceous material forming comedones (commonly referred to as 'blackheads'). Secondary bacterial infection may lead to folliculitis (inflammation of the hair follicles) and formation of papules and pustules from which beads of pus may be expressed. In severe cases, many hair follicles are affected and areas of skin infection (pyoderma) develop, with swelling, inflammation, discomfort and discharge of pus. The point of the chin may become very swollen.
Problems in Persians – idiopathic facial pruritus
A severe form of the condition has been reported in Persians and is known as 'idiopathic Persian facial dermatitis'. This can be very difficult to manage with the skin showing a black waxy material on the hairs in a symmetrical pattern on the face, but particularly the chin and around the eyes.
Treatment of cases of feline acne and stud tail involves removal of excess sebum and hence prevention of comedone formation and secondary infection.
An antibacterial wash, such as chlorhexidine, can be used for this purpose, initially two or three times daily. In mild cases no further treatment is necessary, but in cases showing extensive secondary infection, antibiotic therapy (best selected on the basis of bacterial culture and sensitivity tests) will be required. Occasionally fungal infections (yeasts or dermatophytes/ringworm) may also be involved.
Topical preparations are of very limited value for severe cases, as they are soon licked or cleaned off by cats, and oral antibiotics are usually required for 4-6 weeks. Severe cases may also need short-term treatment with steroids to reduce the inflammation.
Keeping the acne at bay may require clipping of the hair and daily application of topical medications including:
- Chlorhexidine washes
- Use of ceramic (or metal) rather than plastic food bowls has been reported to help in some cases
- Keeping the chin clean after feeding may also help to reduce the problem