Dermato Flashcards

Question

What is leukocytoclastic vasculitis ?

Answer 1

**Photoaggravated vasculitis** : common in horses with white hair and pink skin on their lower limbs. Immune deposits of IgG or complement around the vessel walls. Role of **UV light**, **drug reaction** and **staph infection**. Painful

Answer 2

**Scaling**, **crusting**, and **alopecia** on face, trunk and limbs → **generalized exfoliative dermatitis**. Mane and tail are spared. DDX : - **Sarcoidosis** (idiopathic granulomatous disease) - Dermatophilosis - Dermatophytosis - Pemphigus foliaceus - Seborrhea - Systemic lupus erythematosus - MEED - Toxicosis (arsenic, iodine)

Answer 3

**Sarcoidosis** : generalized or localized exfoliative dermatitis +/- granulomatous inflammation of multiple organs. Skin biopsy → sarcoidal **granulomatous** dermatitis, with numerous **multinucleated histyocytic giant cells** (photo). Spread of disease in lungs, liver, GI, lymphadenopathy. TT : cortico + omega 3/6 + pentoxifylline. Variable prognosis

Answer 4

**MEED** Scaling, crusting, **ulceration** and **alopecia** on the face and **coronary bands** +/- trunk → **generalized exfoliative dermatitis** in young horses (< 4 yo). Predisposition of SB. Accompanied by weight loss, ventral edema, **hypoalbuminemia**, anemia, leukocytosis and neutrophilia, rare eosinophilia. Involvement of multiple organs →GI, liver, lungs, LN, kidneys... DDX : - **MEED** - Sarcoidosis (idiopathic granulomatous disease) - Dermatophilosis - Dermatophytosis - Pemphigus foliaceus - Seborrhea - Systemic lupus erythematosus - Toxicosis (arsenic, iodine)

Answer 5

History + clinical exam + skin and multiple organ biopsies - Skin biopsy → typical **epitheliotropic** infiltration of **eosinophils and lymphocytes** (photo) - Rectal & duodenum → eosinophilic infiltration → intestinal malabsorption - Liver, LN biopsies TT → cortico. Guarded prognosis

Answer 6

Ulcerative lesions in the lightly pigmented skin +/- prurit, pain → **photosensitization** DDx : - primary PS - secondary PS (hepatic injury) - **Dermatophilus infection** (characteristic circular lesions) → excessive inflammatory response in the skin, which can trigger vasculitis upon UV exposure. Histo : diffuse necrotizing and fibrosing dermatitis

Answer 7

**Laser surgical resection** is the most appropriate first-line treatment in the majority of cases due to its high success rates and ease of availibility. **Diode laser excision** → success rate **83%**, with wider zone of damage, which may be more likely to achieve clean "margins". Prolonged healing time, minimal signs of pain. **Carbon dioxide laser** → success rate **65%** Higher recurrence rates with verrucose sarcoids. ## Footnote VetClinics 2024

Answer 8

Answer: C) eca-miR-331 could be used in combination with other biomarkers to improve diagnostic accuracy for ES. **Serum eca-miR-331** expression is neither sensitive nor specific enough as a single ES biomarker. If combined with other miRNAs, it may be helpful for ES diagnosis. Eca-miR-331 expression did not discriminate between horses with **ES and other skin tumors**. Expression of eca-miR-100 and eca-miR-1 was not different between ES and controls. ## Footnote Diagnostic potential of three serum microRNAs as biomarkers for equine sarcoid disease in horses and donkeys jvim 2021

Answer 9

Answer A We found indications that **horse-specific mutations** might exist in subpopulations of equine derived BPV-1/− 2, but these did **not result in horse-adapted genetic variants**. Based on these observations, cross-species transmission from cattle to horses seems to be an **ongoing process**, rather than an ancient occurrence that has been followed by the circulation of horse-adapted BPV variants in the horse population. ## Footnote Complete genomic characterization of bovine papillomavirus type 1 and 2 strains infers ongoing cross-species transmission between cattle and horses Vet J 2023

Answer 10

**Radiotherapy** is considered the “gold standard” for periocular sarcoids, but its high cost and limited availability are significant barriers. **Strontium plesiotherapy** is a locally applied, superficial form of radiotherapy described for the treatment of sarcoids. It appears to be very effective. However, it is only suitable for use in the treatment of **very small, superficial lesions** due to its **limited penetration**. It is simple, cost-effective, does not require isolation of the horse, and usually requires only standing sedation, but it has very limited availability. No significant short or long-term adverse effects were noted apart from **local leucotrichia, leukoderma and alopecia.** ## Footnote Strontium plesiotherapy for the treatment of sarcoids in the horse eve 2020 VetClinics 2024

Answer 11

**Strontium plesiotherapy** appears to be an effective and safe method of treating selected sarcoids (complete resolution in all 10 cases). Longer term follow-up is required to determine the risk of recurrence of treated lesions. ## Footnote Strontium plesiotherapy for the treatment of sarcoids in the horse eve 2020

Answer 12

Equine sarcoids Sarcoids are histopathologically characterised by **plump** (dodu), **randomly arranged spindle-shaped fibroblasts within the dermis**, mild/moderate atypia, and variable number of mitotic figures, often on the low end. Histopathology of an excised sarcoid has similarities to that of **schwannomas**, **exuberant granulation tissue**, or other **mesenchymal neoplasms**.

Answer 13

PCR-based screening of **FNA** for BPV-1/−2 represents a valid method to improve the consistency and quality of sarcoid diagnosis. FNA is a rapid and easily performed procedure. It allows for BPV detection in **both ulcerated and non-ulcerated sarcoids** and concurrently prevents false positive results from superficial contamination. ## Footnote Cross-sectional comparison of superficial swab and fine-needle aspiration: Improving the diagnostic workup of horses with sarcoids Vet. J 2022

Answer 14

BPV-1, BPV-2, and BPV-13 (recently isolated in Brazil, but not in Austria) ## Footnote Screening for bovine papillomavirus type 13 (BPV13) in a European population of sarcoid- bearing equids EVJ 2022

Answer 15

Tumor size decreased in **86% of the horses**, and the median time to first response was **89 days**. Adverse events were minimal and included transient focal inflammation in 2 horses. ## Footnote ALVAC-fIL2, a feline interleukin-2 immunomodulator, as a treatment for sarcoids in horses: A pilot study JVIM 2022

Answer 16

No statistically significant difference in the effectiveness of systemic mistletoe extract (PO and SC) versus placebo against equine sarcoids ## Footnote A randomized placebo-controlled double-blinded study comparing oral and subcutaneous administration of mistletoe extract for the treatment of equine sarcoid disease JVIM 2024

Answer 17

Answer: B A: INCORRECT The study found no statistically significant difference in effectiveness between oral VAE, SC VAE, and placebo, with a P-value of 0.336 indicating no statistical significance. Furthermore, spontaneous regression was observed in 2 horses from the placebo group, meaning the statement that there were "no cases of spontaneous regression in the placebo group" is also false. B) Correct: Both oral VAE and SC VAE showed similar rates of complete or partial regression, but there was no statistically significant difference in effectiveness compared to placebo. Additionally, spontaneous regression was noted in the placebo group. C)Incorrect: Spontaneous regression did occur, specifically in the placebo group (2 horses), and the study did not conclude that SC VAE was significantly better than oral VAE. Both treatments had similar clinical responses, with no statistical significance. D) Incorrect: The P-value was 0.336, indicating that the difference was not statistically significant, and there was no superiority of SC VAE over oral VAE. ## Footnote A randomized placebo-controlled double-blinded study comparing oral and subcutaneous administration of mistletoe extract for the treatment of equine sarcoid disease jvim 2024

Answer 18

Some risk factors for sarcoid re-growth have been identified, including **size**, **repeated treatment**, and **periocular location**. ## Footnote Histological evidence of superficial inflammation is associated with lower recurrence of equine sarcoids following surgical removal: A follow-up study of 106 tumours in 64 horses Vet J 23

Answer 19

**Superficial inflammation** was significantly associated with reduced odds of recurrence of equine sarcoids at their original surgical removal site. It is noteworthy that treatments for equine sarcoids, such as the topical chemotherapeutic agents **5-fluorouracil** and **imiquimod**, probably work by inducing ulceration and active inflammation. ## Footnote Histological evidence of superficial inflammation is associated with lower recurrence of equine sarcoids following surgical removal: A follow-up study of 106 tumours in 64 horses Vet. J. 2023

Answer 20

**BPV-1, 2 and 13** : equine sarcoids **Equus caballus EcPV-1** : oral warts of young horses **EcPV-2** : genital papillomas **EcPV-1 to 9** : aural plague **Equus asinus EaPV-1 to 3** : disease ? ## Footnote Novel equid papillomavirus from domestic donkey evj 2024

Answer 21

SCC → second most common equine tumor Predisposing factors: - **Age** : incidence increases with age - **UV light** : predisposition of depigmented skin, anatomic areas of sun-exposed skin (ocular) - **Equine papillomavirus** : chronic inflammation is a well-known risk factor, link between SCC (genitalia, gastric and head) and **EPV-2** → upregulation of oncogene E6 ? One recent study isolated **EPV-7** in equine penile SCC. - **Genetics** : limbal and nictitating membrane SCC in **Haflingers** → mutation in proteins involve in repair UV-induced DNA damage. ## Footnote VetClinics 2024

Answer 22

**Cyclooxygenase-1 and 2 (COX-1 and COX-2)** are frequently upregulated in equine SCC. But the role of COX-2 over-expression in equine SCC is not yet understood. ## Footnote VetClinics 2024

Answer 23

**G1**: Well-differentiated tumors have minimal basal / parabasal atypica. **G2**: Moderately differentiated tumors are those not fitting with the criteria described for G1 or G3. **G3**: Poorly differentiated tumors have minimal or no architectural similarity with normal tissue. **Metastasis** was present with 44% of G3 tumors, compared to 25% of G2, and 3% of G1 lesions, and the histologic grade was associated with the prognosis. **Outcomes** worsened with increasing grade. ## Footnote VetClinics 2024

Answer 24

**Surgical excision** with wide margins is the treatment of choice for all SCC. However, **recurrence rates are high**, especially with ocular and periocular SCC (30%). **Radiotherapy** is a useful adjunctive or primary treatment for SCC. **Strontium plesiotherapy** is a useful adjunctive therapy for equine SCC, especially **periocular SCC**, where it improved success rates to between 83% and 100%. **Topical chemotherapy**: - **5-fluorouracil (5-FU)** has been described for the treatment of SCC of the external genitalia with surgical resection and as a sole treatment. - Cisplatin beads - Topical mitomycin C ## Footnote VetClinics 2024

Answer 25

A mutation in **damage-specific DNA binding protein 2** (DDB2) has been established as a **recessive genetic risk factor** for ocular SCC in the **Haflinger breed**. A sample of Belgian horses with unknown SCC phenotype was shown to possess this variant at a **similar frequency** to the Haflinger breed. In the study, homozygosity for DDB2 was significantly associated with ocular SCC. A missense variant, DDB2, is a risk factor for **ocular SCC in Belgian horses**. A genetic risk test is commercially available. An association between disease and coat colour loci was not identified. ## Footnote A missense mutation in damage-specific DNA binding protein 2 is a genetic risk factor for ocular squamous cell carcinoma in Belgian horses evj 2020

Answer 26

**EcPV2** is thought to cause **papillomas of the genitals** and **SCC of the genitals, oropharynx, and stomach**. These results suggest **EcPV7** could cause a subset of **equine penile SCC** +/- oropharyngeal SCC. If EcPV7 causes a proportion of equine penile SCC, vaccines to prevent EcPV2 infection may not prevent all equine penile SCC. **EcPV3, 4, 5, 6** cause aural plaques ## Footnote Equus caballus papillomavirus Type 7 is a rare cause of equine penile squamous cell carcinomas Vet J 2024

Answer 27

Three samples of different ‘bloodroot’ preparations were tested. The studied products contained between **11.6% and 25% zinc chloride (ZnCl2).** Veterinarians should be aware that ‘herbal’ or ‘black salve’ preparations intended for the treatment of equine cutaneous neoplasms may contain significant amounts of **zinc chloride (ZnCl2), a caustic, corrosive chemical.** ## Footnote ‘Herbal’ preparations for equine dermal neoplasms contain large amounts of zinc chloride eve 2020

Answer 28

**Urticaria** Frequent causes : ■ **Atopic dermatitis** (environmental allergy → pollens, molds, etc) ■ Drugs and medications ■ **Insect/mite bites or stings** ■ Chemical contact (plants, dyes, detergents, soaps, insecticides, etc.) Less common causes: ■ **Dermatophytes (ringworm)** ■ **Pemphigus foliaceus** (auto-immune skin disease) ■ Stress ■ Vasculitis (including purpura hemorrhagica) ■ Pressure or trauma to the skin ■ Cold ■ Exercise ■ Feed

Answer 29

Alopecia + papules ■ **Dermatophytosis** (ringworm) ■ Staphylococcal infection ■ Alopecia areata (rare autoimmune skin disease) ■ Dermatophilosis

Answer 30

If seasonal → **summer sores (habronemiasis)** Summer sores develop when the larvae are deposited in **previously damaged skin** or **mucous membranes** such as the lips, nostrils or genitalia where they cannot complete the life cycle and instead cause a local inflammatory reaction. The lesions themselves consist of areas of ulceration that usually contain small, gritty, yellow nodules (**‘sulfur granules’)**.

Answer 31

Horse with **cutaneous Onchocerca**. Note the round area of alopecia on the forehead, which is one of the classic presentations of cutaneous Onchocercasis. It is important to consider that **Culicoides transmits Onchocerca** and that the signs of IBH and Onchocercasis overlap. Onchocerca can manifest with **alopecia and crusting** on the face, chest, and abdomen. One classic lesion is the development of alopecic areas, frequently circular on the forehead of the horse. ## Footnote VetClinics 2024

Answer 32

Note the alopecia, scaling, and depigmentation. **Insect allergic horse** that has developed a **mixed bacterial and yeast infection** on his face because of prolonged use of fly masks ## Footnote VetClinics 2024

Answer 33

**Atopic horse** that manifested his disease with **facial pruritus**. This horse did not have an insect component and his level of pruritus was significantly lower than most horses with insect allergy. The alopecic area on his face was a chronic area of rubbing, thus, the skin has some evidence of scarring from previous flares of the disease. Can also affect limbs → self-trauma ## Footnote VetClinics 2024

Answer 34

Neck and mane of a horse suffering from **insect bite hypersensitivity**. Note the **circular areas of alopecia** consistent with a bacterial infection (**Staphylococcal folliculitis**) and the broken hairs on the mane. ## Footnote VetClinics 2024

Answer 35

**Insect allergic horse** with **Staphylococcal pyoderma** on his face. Note the multiple areas of **circular alopecia** consistent with bacterial folliculitis. ## Footnote VetClinics 2024

Answer 36

1- Cytology and culture → most common **secondary infections** (bacteria, yeasts, mites) 2- Look for allergies 2.1- **Insects**: Consider history and distribution of lesions → agressive repellent protocol and lifestyle changes 2.2- **Environmental/pollen**: Id° of sensitizations (via serology or skin test) and implementation of allergen specific immunotherapy (ASIT). Topical therapy to remove allergens, avoidance of specific hays (alfalfa, peanuts, timothy), hydration of the skin. Non-targeted approach: symptomatic management of residual pruritus (cortico, antihistamines) Immunotherapy for IBH → ineffective Antihistamines for IBH → not recommended Antihistamines for atopic dermatitis (pollens) → 60% improved ## Footnote VetClinics 2024

Answer 37

Allergy testing include serologic tests, enzyme-linked immunosorbent assay (ELISA), radioallergosorbent test , and intradermal testing. There are normal horses that may have some positive results on allergy test, and horses that are pruritic for other reasons that can also show positive results on an allergy test. Thus, a **positive allergy test** does not guarantee that the clinical signs are due to an allergy to the tested allergens. Therefore, the **diagnosis of environmental allergy** is a diagnosis by **exclusion** of other pruritic diseases like infections, mites and insects. Allergy testing is done to figure out **what sensitizations the patient has with the intent of formulating ASIT**. What matters the most is that the allergens are **not selected** based on how high the score is on the test but on how they **correlate with the environment and seasonality** of the patient. ## Footnote VetClinics 2024

Answer 38

**Contact allergy** is a very pruritic condition presenting with a papular eruption. The culprit (coupable) is typically a spray, shampoo, some plants, or shavings. Contact allergy is **delayed type hypersensitivity**, thus, the clinical signs occur **24-48 hours after** exposure and that makes it sometimes difficult to exactly figure out what the trigger is. Contact allergy is **not histamine-mediated**, thus, antihistamines are of minimal benefit. Only **glucocorticoids** in combination with prompt washing and removal of the offending agent can provide relief. ## Footnote VetClinics 2024

Answer 39

■ **Atopic dermatitis** ■ **IBH** ■ **Allergy** (food, contact, drugs) ■ **Chorioptic / Psoroptic / Sarcoptic mange** ■ Pediculosis (lice) ■ Poultry / Forage mites ■ Trombiculosis (chiggers) ■ Malassezia dermatitis (inguinal area, rear limbs) ■ Oxyuriasis ■ Intestinal parasite HS

Answer 40

Symmetrical pruritic papules, all over the neck, shoulders, chest, lateral thoracic area. Most common cause → **infectious folliculitis** DDX : ■ Bacterial (Staph, Dermatophilus) ■ Dermatophytosis ■ other **Eosinophilic granuloma** : papules, nodules symmetrically distributed along the body/trunk, +/- pruritic. DDX : ■ Infectious granulomas ■ Sterile granulomas ■ Neoplasms (mast cells, lymphoma) ■ Cysts

Answer 41

IBH is a **type I** and **type IV hypersensitivity**. It is now known that cytokines like **IL-4, IL-13, IL-5, and IL-31** are important. In the study, there was a strong reduction in circulating **eosinophil counts** after vaccination against IL-5. Additionally, there were reduced **basophil counts**, but only in the 2nd year of vaccination, suggesting a bystander effect of the anti-IL-5 vaccine on basophil counts. Although experimental studies have explored the concept of autovaccination against these cytokines with encouraging results, in clinical practice, at this time, veterinarians have limited treatments to minimize the pruritus. ## Footnote Targeting eosinophils by active vaccination against interleukin-5 reduces basophil counts in horses with insect bite hypersensitivity in the 2nd year of vaccination Vet J 22

Answer 42

- **Pemphigus** - Severe **bacterial foliculitis** (degenerated neutrophils release proteolytic enzymes) - **Dermatophytosis** (*Trichophyton equinum*) - **Dermatophilosis** Thus, it is critical for clinicians to interpret the finding of **acantholytic cells** and not immediately jump to the conclusion that all patients with acantholytic cells have pemphigus. ## Footnote VetClinics 2024

Answer 43

- **Idiopathic** - Trggered by **drugs** - **Vaccines** - Neoplasia (**paraneoplastic pemphigus**) Clinicians are always encouraged to always look for a trigger, whether **drugs, vaccines, or cancer** anytime pemphigus is diagnosed to increase the chances of a positive outcome for the patient and remove the trigger. *Histopathology of pemphigus foliaceus in a horse. Note the area of splitting right below the stratum corneous and the formation of acantholytic cells, pink epithelial cells losing contact with each other.* ## Footnote VetClinics 2024

Answer 44

Ulcerative lesion in the oral cavity - **Bullous pemphygoid** (no acantholytic cells) - **Pemphigus vulgaris** - Toxic epidermal necrolysis or vasculitis (secondary to drugs, infection, or vaccination) ## Footnote VetClinics 2024

Answer 45

Pathogens that infect endothelial cells and cause primary vasculitis include: - African Horse Sickness (AHS) - EVA - Equine granulocytic anaplasmosis - EIA ## Footnote VetClinics 2024

Answer 46

PH secondary to: - **Streptococcus equi equi** - **Corynebacterium pseudotuberculosis** - Strep equi zooepidemicus - **Rhodococcus equi** - EIV (rare) - EVA (rare) - EHV-1 (rare) ## Footnote VetClinics 2024

Answer 47

- **Penicillin** - **Potentiated sulfonamides** - Ceftiofur - Rifampicin - ACP - detomidine - tiludronate - mycobactrium-cell wall extract used for the TT of sarcoids ## Footnote VetClinics 2024

Dermato Flashcards

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