Hookworm Dermatitis Flashcards
Differentials for Hookworm Dermatitis/Cutaneous Larva Migrans
Diagnostic Testing
Pathogenesis
Treatment
Contact hypersensitivity, Scabies/Demodex, Dermatophytosis, Pyoderma/pododermatitis, bullous pemphigoid, lupoid onychodystrophy
Cytology, Skin scrape, DTM culture/pcr, eventual biopsy
L3 larva penetrate epidermis through cornified layer, pushing against keratinocytes and undulating deeper towards dermis
heartworm prevention kills adult hookworms in GI tract, Fenbendazole 50mg/kg PO q24 x3d, consider treatment for itch (steroids?), concurrent topical antiseptic or oral antibiotics/antifungal pending cytology
Uncinaria stenocephala
Ireland, parts of England, and United States, cutaneous lesions more common with U. Stenocephala
With natural and experimental infections similar clinical and histologic lesions
Enter through area of desquamation or hair follicle, horny layer parallel to skin surface, little evidence of enzymatic activity, undulation creates pressure and forward movement by pushing against rigid keratinocytes through least resistance of outer layers, little hindrance by dermis and cells reunite after passage of larvae leaving little evidence of migration, other species however cause loss of integrity of the epidermis during penetration
Reservoir host is dogs and cats, skin lesions not as severe for A. Braziliense, A. Caninum, and U. Stenocephala as these are their hosts, skin lesions incidental to completion of the life cycle though rarely mature if enter percutaneously (A. Caninum can)
Signalment and Clinical signs of hookworm dermatitis
Signalment: animals exposed to grass and soil of runs and paddocks in spring and summer in cool climates, kenneled dogs on grass or earth runs with poor sanitation, Ancylostoma spp. most common in canines of subtropical or tropical regions of the world, U. Stenocephala in foxes in cooler climates
Clinical signs: red papules on contact surfaces, progressing to uniformly erythematous and then thickened and alopecic (feet in particular but also sternum, ventral abdomen, posteromedial thighs, and tail; bony prominences of elbows, hocks, and ischial tuberosities may have more obvious lesions due to thickened skin and hair loss; erythematous interdigital webs, feet may be swollen, painful, and hot; footpads become spongy and soft particularly at pad margins where the tissue can be readily grooved and stripped from the underlying dermis). Chronically inflamed foot pads become variably hyperkeratotic, chronic inflammation causes rapid growth and deformity of claws, may be friable and break off leaving thick tapered stumps. Possible arthritis of interphalangeal joints. Varied intensity of pruritus but always present. In people called creeping eruption.
Histopath and Diagnosis of Hookworm dermatitis
Treatment
Histopath: varying degrees of hyperplastic or spongiotic perivascular dermatitis with eosinophils and neutrophils, possible recent migration tracts in epidermis and may be traced into the dermis as linear tracts of neutrophils and eosinophils, larvae rarely found but if present surrounded by clusters of neuts, eos, and mononuclear cells, hypersensitivity may be a cause of lesions
Dx: clinical signs, eggs on fecal, history
Ddx: demodex, contact dermatitis, Pelodera dermatitis, and intradermal penetration by other parasites such as Strongyloides and schistosomiases
Treatment: cleaning and fecal decontamination, improved hygiene, and anthelmintic treatment and prophylaxis, trim claws to prevent joint stress and improve foot conformation, keep paws clean and dry
