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Also known as: '''''Summer sores — Granular dermatitis — Bursautee
==Introduction==
Cutaneous '''Habronemiasis''' is a hypersensitivity reaction to the larvae of the nematode species [[Habronema and Draschia spp.|''Habronema'' and ''Draschia'']].
The condition is characterised by '''ulcerative, granulomatous''' skin lesions which do not heal.
==Signalment==
==Signalment==
The condition occurs most commonly in warm wet climates such as the tropics and sub tropics but is also a common skin condition in the UK.
The condition occurs most commonly in warm wet climates such as the tropics and sub tropics but is also a common skin condition in the UK.
It affects moist regions of the body and open wounds and has a seasonal occurance whihc partially or fully resolves over the winter.
It affects moist regions of the body and open wounds; it typically has a seasonal distribution with partial or full resolution during the winter.
==Diagnosis==
===Clinical signs===
===Clinical signs===
Lesions most commonly occur on the legs, ventrum, around the eyes, urethral process and prepuce and at the site of pre-existing wounds.
The lesions are single or multiple ulcerative nodules with a serosanguinous discharge. There may be excessive granulation tissue and small yellow granules of necrotic debris which surround the larvae.
Pruritus may be mild to severe.
In cases of '''conjunctival habronemiasis''' there will be gitty plaques on the conjunctival and palpebral borders, which is painful in severe cases leading to epiphora and blephrospasm. Conjunctival habronemiasis is fairly common and must be differentiated from [[Squamous Cell Carcinoma|squamous cell carcinoma]] of the third eyelid.
===Pathology===
===Cytology===
Cytology of the exudate or skin scrapings frequently reveal larvae but biopsy is recommended because ''Habronema'' larvae commonly invade skin lesions with another underlying cause such as infectious granulomas, [[Sarcoids|sarcoids]] and ulcerative dermatitis.
===Biopsy===
Biopsy will reveal nodular/diffuse granulomatous dermatitis with eosinophilic infiltrates and mast cells. Necrotic foci with multiple nematode larvae and granulation tissue with [[Neutrophils|neutrophils]] along the ulcerated surface are also characteristic.
==Treatment==
==Treatment==
Systemic glucocorticoids decrease the inflammatory response of the the hypersensitivity reaction, oral prednisolone is effective at a dose of 1mg/kg SID or BID for 14days and then tapered.
Systemic '''glucocorticoids''' decrease the inflammatory response of the the hypersensitivity reaction, e.g. oral prednisolone.
Organophosphate pastes and anti-inflammatory pastes can be applied to the wound until it has healed, or thye wound should be bandaged to prevent reinfestation.
Organophosphate pastes and anti-inflammatory pastes can be applied to the wound until it has healed, or the wound should be bandaged to prevent reinfestation.
Excessive granulation tissue should be removed surgically.
Excessive granulation tissue should be removed surgically.
The conjunctival form can be treated with topical ivermectin eye drops with a pH of 7.4.
Ivermectin or appropriate anthelmintics should be used to limit nematode infestation, fly control will also reduce exposure to the larvae.
Ivermectin or appropriate anthelmintics should be used to limit nematode infestation, fly control will also reduce exposure to the larvae.
==Prognosis==
==Prognosis==
Recurrence is common. Fly control, meticulus wound management and regular anthelmintic use is needed to prevent or limit the condition.
Recurrence is common. Fly control, meticulous wound management and regular anthelmintic use is needed to prevent or limit the condition.
<big>'''See also [[Spirurids - Donkey|Habronemiasis in Donkeys]]'''</big>
{{Learning
|literature search = [http://www.cabdirect.org/search.html?q=%28%28title%3A%28%22Cutaneous%22%29+AND+title%3A%28%22Habronemiasis%22%29%29+OR+title%3A%28%22Summer+sores%22%29+OR+title%3A%28%22Granular+dermatitis%22%29+OR+title%3A%28Bursautee%29%29+AND+od%3A%28horses%29 Cutaneous habronemiasis publications]
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==References==
==References==
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[[Category:To_Do_- lizzyk]]
[[Category:Expert_Review]]
[[Category:Dermatological Diseases - Horse]]
[[Category:Integumentary System - Helminth Infections]]