SUMMER SKIN

Roles of equine skin

Protection

• Provides a physical barrier against the environment
• Protecting the horse’s system from injury, infection and harmful substances

Temperature regulation

• Warm through insulation from trapped air in the longer hair over winter, and also from the subcutaneous fat layer
• Cool through sweating via the sweat glands of the skin, where sweat evaporates and cools the body

Sensory perception

• Contains nerve endings allowing the horse to sense touch, pressure, pain and temperature

Other

• Production of appendages such as hooves
• Pigmentation of the fair follicles, which gives the horse its coat colour
• Production of sebum, an oily substance to keep hair soft and pliable

For seasonally sensitive individuals, maintaining summer skin health can be particularly challenging.

SWEET ITCH

Culicoides hypersensitivity, known as sweet itch, is a common allergic skin condition affecting horses. Caused by a reaction to the bites of Culicoides midges—tiny, flying insects that are so small they are sometimes referred to as “no-see-ums”. This condition can cause intense itching, hair loss and skin damage. Sweet itch can significantly affect a horse’s welfare, behaviour and appearance, especially over the warmer months when midges are most active.

Culicoides midges are most active during spring, summer and early autumn, particularly around dawn and dusk. These tiny insects thrive in warm, moist environments, such as near standing water, marshy fields, or manure heaps.

Sweet itch signs

Clinical signs typically become noticeable in late spring or early summer, intensify through the season before usually subsiding as temperatures drop.

• Intense Itching (Pruritus): Horses often exhibit relentless itching, rubbing themselves against fences, trees, or stable walls to relieve discomfort.
• Hair Loss: Persistent rubbing leads to patchy hair loss, particularly around the mane, tail base, withers, belly, and face.
• Thickened, Scabby Skin: Over time, affected areas can become thickened, crusty, and inflamed due to trauma and secondary infection.
• Open Sores and Bleeding: Chronic rubbing and biting can lead to open lesions that may attract flies and become infected.
• Behavioural Changes: Due to constant irritation, some horses may become restless, anxious, or unwilling to be handled or ridden.

Sweet itch is often seasonally recurrent, with the same pattern of symptoms reappearing year after year unless proactive steps are taken.

Management

Veterinary treatment may include anti-inflammatories to control the itching, and antihistamines, although results can be disappointing in horses compared to other species, such as people and dogs.

Owner management is vital to a successful outcome. Nutritional management can nourish healthy skin from the inside. Firstly, ensure the diet is balanced, which is necessary for all health and vitality. It can be too easy to assume the lush summer pasture is providing all they need, but it will be micronutrient deficient. Common deficiencies include nutrients such as zinc for skin health and selenium, an important antioxidant. Feeding a broad-spectrum multi-vitamin and mineral supplement or concentrated balancer ensures all those boxes have been ticked.

For those experiencing summer sensitivities, feeding a nutritional complex to support the body’s own anti-inflammatory processes is recommended.

Oils are also recognised, particularly omega 3 fatty acids, such as found in linseed oil or marine oils, which have known benefits for sweet itch.

Note: the research behind linseed was done in Canada so you may find your customers asking for ‘Flax oil’ – which is simply their term for Linseed.

Management tips for controlling sweet itch include:

• Physical Barriers: Full-coverage rugs, including belly, neck and face protection, can be really useful.
• Midges are crepuscular, meaning active at dawn and dusk. Stabling during these periods can be really useful.
• Environmental: Ensure paddocks are kept well poo-picked, and avoid turning out in areas of standing water which attract midges. Ideally, turnout on a hilly field which encourages a breeze, as midges are very poor fliers.
• Insect Repellents: Use a fly repellent regularly. Check for the HSE number to ensure it is legally registered and effective.

KEEP OUT OF THE SUN!

Horses, like ourselves, can also be affected by sunlight, though in a couple of related, but slightly different, ways.

Sunburn

Just like humans, horses can be susceptible, particularly on light-coloured skin or areas of little hair – such as around the muzzle. Face masks, which cover the muzzle, can be really useful.

Consider stabling them in the heat of the day. They’ll thank you for it, for being out of the sun, away from flies and keeping cool!

Photosensitization

Caused by toxin ingestion resulting in a sunburn like reaction.

Primary photosensitization from ingesting circulating photodynamic compounds causing oxidative damage at the skin surface. Causative agents include St John’s Wort, mycotoxins in mouldy feed and certain chemicals.

Secondary photosensitization is when toxins result in liver damage, so negatively impacts the liver’s ability to excrete toxins leading to skin damage. Ragwort is a key cause, particularly over time. Whilst relatively unpalatable in its fresh state, care must be taken to avoid ragwort in hay or haylage, where it is more readily ingested.

In conclusion, whilst our horses and ponies appreciate feeling the warmth of the sun as much as we do, care should be taken to protect them from skin damage either via insect hypersensitivity or UV sensitivity.