Feline acne is probably more common than is generally appreciated, as most cases are mild and pass unnoticed. More severe cases, however, may respond slowly to treatment and seriously detract from the appearance of the cat.

Two main types of gland are found in the dermal layer of the skin of the cat - the sweat glands and the sebaceous glands. Most of the sebaceous glands are associated with hair follicles and produce an 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 oily secretion of these larger sebaceous glands appears to have a role in territorial 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, greasy patches. Cat owners may have noticed that they are 'marked' by their pets on returning home. Cats will also often mark certain objects at feeding time.

Overactivity of the submental organs is a relatively common finding and 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 materialonthe chin which may bemistaken for flea dirt; this is sometimes called 'cruddy chin'.

Overactivity of the glands at the base of the tail is often known as 'stud tail'. It has been suggested that activity of the supracaudal organ around the base of the tail depends on testosterone (the male hormone). Stud tail is most common in entire males, but, despite its name, is also seen in neuters and females.

 

This overactivity of the sebaceous glands predisposes to feline acne which is seen in varying degrees of severity. The condition remains poorly understood in terms of an underlying cause and is assumed to represent a form of keratinisation (keratin is a protein which is the main component of hair and nails) disorder where the cat's hair follicles produce excessive keratinous/sebaceous material. It may occur at any age and in any breed or sex. In mild cases, the associated hair follicles become plugged with the black sebaceous material forming comedones (commonly referred to as a blackhead). Secondary bacterial infection may result, leading to folliculitis (inflammation of the hair follicles) and formation of papules and pustules from which beads of pus may be expressed. In severe cases of inflammation of multiple follicles, pyoderma ( an eruption characterised by pus in the skin) develops, with a mass of discharging tracts or sinuses. Cats with mild feline acne or stud tail show no associated clinical signs but in severe cases there may be inflammation and irritation of the overlying skin. The point of the chin may become grossly swollen and there may be an enlargement of the draining lymph nodes of the head and neck.
 

Treatment  

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 surgical scrub, such as chlorhexidine, can initially be used for this purpose two or three times daily. In mild cases no further treatment is necessary, but in cases showing extensive secondary infection, antibiotic therapy, preferably selected on the basis of bacterial culture and sensitivity tests, will be required.

Topical preparations are of very limited value for severe cases because they are soon licked or cleaned off by the patient, and antibiotics should be given orally for four to six weeks. Severe cases may also be treated with steroids to reduce the inflammation. Keeping the acne at bay may require clipping and daily application of chlorhexidine. Other treatments which have been tried include mupirocin (Bactroban - a human drug not licenced for use in cats). Topical retinoids may be considered for long term control of a mild case. Supplementation with essential fatty acids (evening primrose oil/fish oil) orally on a daily basis has been reported to help some cases. Most cases respond satisfactorily but some cases with serious secondary infection may require prolonged treatment.

There may be recurrence and in some cases the only method of controlling the excessive sebum secretion is to continue daily cleansing indefinitely.

Occasionally acne is associated with fungal infections including dematophytosis (ringworm) and, rarely, with demodectic mange.

Problems in Persians  

A severe form of the condition is reported in Persians - it is known as idiopathic Persian facial dermatitis - some veterinary surgeons call it 'dirty face'. It can be very difficult to manage. The skin of such cats shows a black waxy material on the hairs in a symmetrical pattern on the face, but particularly the chin and around the eyes.

Prevention  

In some cats with a tendency to chin acne, the use of ceramic or metal feeding dishes, instead of plastic ones, may help to prevent the problem from recurring or deteriorating. Chin acne is sometimes more severe in cats which are messy feeders, so scrupulous attention to hygiene after meals, or a change to food which can be eaten more neatly, may help to reduce the problem.