ABSTRACT: Skin conditions occur more frequently in summer months, either as the result of the hotter and more humid weather, or environmental factors such as exposure to grass awns. Increased time outside can increase these risks. Numbers of ectoparasites also increase in the summer and autumn. This paper discusses advising owners about possible conditions, how to spot them and how to prevent problems occurring, especially in dogs and cats predisposed to skin disease.

Summertime. Long days of unbroken sunshine, walking the dog in wildflower meadows – but also time to consider the possible adverse effects of the summer weather on dog and cat skin and what suitable advice to give to owners to protect their pets.

Problems associated with warmer weather can result either as a direct effect of the increased sunshine, heat and humidity, or as an effect of exposure to seasonal insults, such as grass awns or ectoparasites.

This article will consider the possible problems, advice to give to avoid problems and signs of disease for which owners should be alert.

Exposure to sunlight

Direct exposure to sunlight can cause problems in cat and dog skin where the hair coat is either deficient (sparsely haired areas or where alopecia is present), or where the pigment is lacking skin and hair coat (white ears on cats and sunbathing bull terriers).

The first signs of sunburn (actinic damage) are erythema and scaling. Sunburn is a particular problem in white pinnae (Figure 1) and lower eyelids of cats; but the ventral skin in white bull terriers can be affected, as can bald areas in dogs with endocrine disease or symmetrical (seasonal) flank alopecia (Figure 2).

Figure 1: Cat pinna showing early actinic damage

Figure 2: Pointer with symmetrical alopecia and actinic damage

Alopecic breeds of dog and cat (Mexican Hairless and Chinese Crested dogs, Sphinx and Devon Rex cats) are also at risk from actinic damage.

These early signs of actinic damage are very important, as they are easily reversed by reducing exposure to sunlight at the hottest times of day, together with the application of a high-factor, water- resistant sunblock to affected areas.

If exposure to sunlight continues, then the scaling increases and can overlie areas of erosion. Curling of the edges of the pinnal cartilage may be seen, and these signs can develop into squamous cell carcinoma in both dogs and cats. 

Rarely, haemangioma or haemangio- sarcoma may also be induced in dogs by actinic damage.

Another condition that appears to be sensitive to direct sunlight is discoid lupus-like disease in the dog, especially when affecting the nasal planum (Figure 3). The author has seen dogs with significant lupus-like lesions on the nose in summertime, which completely resolve each winter.

Figure 3: Discoid lupus-like disease on the nasal planum

Increased temperature and humidity

Summer weather can also be associated with an increase in pathogens on the skin surface. Dense-coated dogs – especially those predisposed to secondary skin infections (hot spots, pyoderma or Malassezia yeast dermatitis) – are more often affected when the weather is hot and humid.

Underlying conditions, such as allergies (atopic dermatitis and flea allergic dermatitis, both more frequent in the summer) often predispose to such infections (Figures 4 & 5).

Figure 4: Malassezia otitis in an atopic dog 

Figure 5: Pododermatitis in an atopic dog

Regular washing with antibacterial, antifungal and emollient shampoos can remove allergens and reduce the build-up of potential pathogens. A good working knowledge of different shampoos – including the unlicensed ones – and their active ingredients, is very useful.

Skin folds, including feet, axillae, groin and ventral neck, are often affected. Ears can also be considered as skin folds in this context; and otitis externa is more frequent after warm and humid weather.

In predisposed dogs, the regular use of an antiseptic ear cleaner can prevent infection occurring. Clipping for the summer can also be helpful, although care needs to be taken, as some dogs can flare up after a clip; and beware post¬clipping alopecia in sled breeds!

All dogs b
enefit from regular grooming in the summer to remove any retained coat after moulting.

Foreign bodies

Perhaps the commonest cause of specific skin disease seen in the summer is the damage caused by grass awns – either by penetration of the skin of feet or other skin folds; or by finding their way into ear canals. Foreign body abscesses can appear some distance from where they penetrate the skin, and the awns can be troublesome to find.

Breeds with dense fur and pendulous pinnae are at particular risk. Advising owners to check their dogs’ feet and ears for grass awns regularly can prevent needless anaesthesia and trauma. 

Occasionally, blackthorns may penetrate the skin of thin-coated breeds and can be particularly difficult to locate.

Swimming

Whilst swimming can be excellent exercise in the summer, dogs that are prone to skin disease may experience flare-ups of skin disease if regularly left damp. This is also true for dogs with recurrent otitis.

Seawater is usually clean and rarely a problem; but the accumulation of sand in skin folds can be abrasive and irritant, and it should be rinsed off with clean water as soon as possible.

Ectoparasites

The summer brings with it an increased level of ectoparasites, with flea and tick numbers increasing in late summer, together with the appearance of harvest mites. Allergic skin disease can accompany each of these, with flea allergic dermatitis still the commonest skin disease in both dogs and cats (Figures 6 & 7).

Figure 6: Dorsal pruritus and self-trauma in a dog with flea allergic dermatitis

Figure 7: Symmetrical alopecia in a cat with flea allergy

Owners should be advised about flea- control programmes, incorporating environmental treatment if problems recur or if allergy is present. There are a myriad of different flea-control products available, all with their own benefits and limitations, so it is no surprise that owners often end up confused.

The veterinary nurse can play a vital role in educating owners regarding the best treatment option for their circumstances.

In late summer, in particular, owners should check dogs’ feet for the orange, pinhead-sized larval harvest mites (Trombicula autumnalis), and cat owners should look for them around the head and ears (Figures 8 & 9).

Figure 8: Cat with larval Trombicula mites attached 

Figure 9; Trombicula autumnalis mite larva

Concerns are increasing about tick-borne diseases, and these may become more significant with hotter summers. Owners should be advised to check for ticks, and the correct way to remove them (Figure 10).

Figure 10: Ixodid tick

Behaviour

Spring, and a young cat's fancy turns to thoughts of love – no surprise then that the incidence of cat bite abscesses increases in spring and summer months.

This is time the to remind owners to have their tomcats neutered; before they start fighting or, worse, get run over!

Summary

It would seem common sense to improve skin and coat hygiene, implement flea- control programmes and avoid excessive sun exposure in the summer months. Timely reminders can be good practice and prevent more serious consequences, especially in cats and dogs already at risk owing to underlying skin problems, or the lack of an adequate protective hair coat. 

Author

David Scarff BVetMed CertSAD MRCVS

David Scarff has been practising as a veterinary dermatologist – initially at the Royal Veterinary College and then in practice – for more years than he is prepared to admit. He believes that good skin hygiene is paramount in preventing the recurrent skin infections seen in allergic dogs, and that the role of the veterinary nurse in giving advice about routine skin care and ectoparasite control is essential.

To cite this article use either

DOI: 10.1111/j.2045-0648 2012.00190.x or Veterinary Nursing Journal Vol 27 pp 253-255

 

 

 

 

Veterinary Nursing Journal • VOL 27 • July 2012 •