Enlighten your approach to dermatology

Content sponsored by Vetoquinol.

Dermatological cases run the gamut from uncom- plicated allergic disease to deep pyoderma to severe autoimmune diseases. As veterinarians, champions of antimicrobial stewardship, and promoters of evidence-based medicine, we are always on the lookout for novel therapies that limit the use of systemic antibiotics and anti-inflammatories and offer safe, noninvasive treatment options. This is where Vetoquinol’s Phovia has come out as a shining star—pun fully intended.

Easy to use

The Phovia kit contains an LED light that emits blue, low-level energy (peak wavelengths 440-460 nm) and a chromophore gel that is activated by fluorescent light energy (FLE). The gel is applied in a 2-mm–thick layer and the light is held 5 cm from the skin in a 2-minute automated cycle. The skin is then cleaned with saline and the process is repeated a second time. These 2 gel and light applications make up 1 treatment session. In total, the treatment takes no more than 10 minutes and may be applied by veterinary technicians or assistants.

How it works

Phovia uses a type of photobiomodulation (PBM) that uses broader wavelengths with lower energy that can penetrate the skin and stimulate healing.¹ PBM excites chromophores in the mitochondria, which then begin making energy in the form of adenosine triphosphate. This has a multipurpose downstream effect of modifying biological processes, which stimulates the secretion of numerous important growth factors including epidermal growth factor, vascular endothelial growth factor, fibroblast growth factors, and transforming growth factor beta, and also increases collagen production.^1,2 PBM also works by stimulating photosensitizers to react with ambient oxygen and produce reactive oxygen species that kill microorganisms.³ These physiologic effects improve wound healing and reduce inflammation and bacterial contamination. This gives Phovia a broad array of clinical applications, including therapy for nonhealing wounds, deep pyoderma, and severe inflammatory processes.

Safety

Phovia is extremely safe and well tolerated by the vast majority of patients, even the cranky cats. The tissue being treated may become slightly warm to the touch, but this is to be expected. FLE therapy is not indicated for use in photosensitivity conditions (such as facial discoid lupus erythematosus) or when photosensitizing medications are being used (such as topical retinoids or systemic tetracyclines).

It's evidence-based medicine

Phovia isn’t just a cool light trick. Numerous studies have demonstrated the value of PBL and there are a number of papers in veterinary literature demonstrating the efficacy of Phovia specifically. For deep pyoderma, a prospective, blinded, randomized, controlled clinical trial demonstrated that Phovia used in combination with systemic antibiotics significantly reduced the time to complete resolution (4.3 +/– 1.3 weeks) compared with the use of systemic antibiotics alone (15.5 +/– 3 weeks).⁴ A prospective, controlled study assessed the use of Phovia in accelerating surgical site wound healing and the results found that Phovia-treated tissue showed promise for improving wound healing by stimulating the release of cytokines, which promote wound healing, as well as promoting a more complete repair of the damaged tissue.¹ For the treatment of canine perianal fistulas, Phovia was used as a sole therapeutic agent and proved to significantly reduce lesions and improve tenesmus, dyschezia, and vocalization when defecating.⁵

Phovia in dermatology

The authors have been successfully using Phovia for many months and continue to find new and exciting clinical applications for light therapy. With most patients, the authors recommend 2 Phovia treatments back-to-back, performed once weekly. This treatment protocol allows for close monitoring of the lesion, providing increased opportunities for early intervention should treatment changes be necessary. We have used Phovia both as a sole therapy as well as in conjunction with other systemic and topical therapies. Below are a number of cases examples in which the authors have been successfully using Phovia (names have been changed for anonymity).

Case 1: Popeye

Day 0

Popeye, a 3-year-old, male, castrated Labrador retriever, was initially presented with a history of a soft-tissue swelling that developed draining tracts in the right mid-flank area. Lesions were first noted 4 months prior. Initially, a drain was placed and cefpodoxime was initiated, with minimal improvement. Biopsy of the lesion and culture and sensitivity (C&S) were performed. The histopathology was consistent with pyogranulomatous dermatitis with furunculosis and fibrosis, and the culture revealed a methicillin-resistant Staphylococcus pseudintermedius. Treatment with trimethoprim sulfa was initiated based on C&S results and had been given for the 6 weeks prior to presentation. Winston had a prior history of allergic dermatitis treated with oclacitinib (Apoquel; Zoetis), which had been discontinued 1 month prior to lesions appearing.

Upon presentation, there was a 7-cm, irregularly shaped area of alopecia over the lateral mid-abdominal region. There were 3 focal draining tracts centered over erythematous to violaceous colored tissue that was slightly raised and swollen. Skin adjacent to and surrounding these swollen areas was slightly thickened and smooth. The deepest draining tract was located ventrally and exuded serosanguineous fluid.

Day 17

Cytological evaluation of the fluid from the draining tract revealed pyogranulomatous inflammation with eosinophils and rare free cocci. A sample of fluid was submitted to MiDOG for DNA sequencing and urine was submitted to MiraVista Diagnostics for blastomyces antigen testing. Repeat biopsy and histopathology were declined. Differential diagnoses included deep fungal or bacterial infection, sterile nodular panniculitis, sterile pyogranulomatous syndrome, migrating foreign body, or neoplasia.

Phovia treatments were initiated once weekly along with starting a tapering course of prednisolone and pentoxifylline to help improve wound healing and reduce inflammation. Phovia treatments were given on days 0, 7, 14, and 17. The urine blastomyces test was negative. Amoxicillin was initiated on day 14 based on DNA identification of an actinomyces spp. This is an ongoing clinical case that has not achieved clinical cure but has shown significant improvement.

Case 2: Cruella

Cruella, a 6-year-old, female, spayed domestic shorthair, was presented with a history of cicatricial alopecia, ischemic dermatopathy, and abnormal collagen found on histopathology from initial presentation at our clinic 5 years prior. Because of Cruella’s collagen defect, her skin would easily tear and was very slow to heal and she had now developed a nonhealing wound in her interscapular skin that was not responding to topical therapy, cyclosporine capsules (Atopica; Elanco), oral dexamethasone, and repeated cefovecin sodium injections (Convenia; Zoetis). Despite recommendations, the pet parent was hesitant to further taper the steroids because of worsening of the lesions.

Day 0

Day 64 (2 months on Phovia)

Upon presentation, there was a 2-cm annular erythematous, moist, erosive lesion interscapularly with crusting at the edges and a central eschar of yellowish tissue. The skin surrounding the lesion was scarred and had evidence of chronic steroid administration (thin, atonic, and alopecic with clearly visible cutaneous vessels). The alopecia extended along the dorsal spine caudally, over the left lateral thigh, and cranially over the top of the head and lateral pinnae.

Weekly Phovia treatments were initiated along with a schedule to taper the dexamethasone because of steroid side effects and concern that the chronic steroid use was further delaying wound healing. Phovia treatments were given on days 0, 8, 15, 22, 29, 36, 57, 64, 71, 78, 85, 92, 99, 108, and 122. This is an ongoing case that has not achieved clinical cure because of the collagen defect but has shown significant improvement.

Day 92 (3 months on Phovia)

Day 122 (4 months on Phovia)

Conclusion

In the authors’ opinion, Phovia is a safe, noninvasive, well-tolerated treatment that has shown clinical benefit when used in a variety of infectious and inflamed disease processes as well as nonhealing wounds. In conjunction with systemic antimicrobials and anti-inflammatories, this treatment modality assists greatly in the resolution of lesions and decreases duration of disease.

Julia E. Miller, DVM, DACVD, is a specialist at the Animal Dermatology Clinic in Louisville, Kentucky. She has a special interest in treating difficult otitis externa and large animal dermatology.

Joya Griffin, DVM, DACVD, became a diplomate of the American College of Veterinary Dermatology in August 2010 and joined the Animal Dermatology Group. She has a special interest in fungal and immune-mediated skin diseases as well as feline and equine dermatology. She enjoys lecturing to fellow veterinarians, mentoring residents, and teaching the veterinary students who extern with her. Griffin also stars in the Nat Geo Wild television series “Pop Goes the Vet with Dr. Joya,” which highlights the challenging and mysterious cases she encounters in veterinary dermatology.

References

1. Salvaggio A, Magi GE, Rossi G, et al. Effect of the topical Klox fluorescence biomodulation system on the healing of canine surgical wounds. Vet Surg. 2020;49(4):719-727. doi:10.1111/vsu.13415
2. Marchegiani A, Spaterna A, Cerquetella M. Current applications and future perspectives of fluorescence light energy biomodulation in veterinary medicine. Vet Sci. 2021;8(2):20. doi:10.3390/vetsci8020020
3. Wang ZX, Kim SH. Effect of photobiomodulation therapy (660 nm) on wound healing of rat skin infected by St aphylococcus. Photobiomodul Photomed Laser Surg. 2020;38(7):419-424. doi:10.1089/photob.2019.4754
4. Marchegiani A, Cerquetella M, Tambella AM, et al. The Klox Biophotonic System, an innovative and integrated approach for the treatment of deep pyoderma in dogs: a preliminary report. Vet Dermatol. 2017;28:545 (abstract).
5. Marchegiani A, Tambella AM, Fruganti A, Spaterna A, Cerquetella M, Paterson S. Management of canine perianal fistula with fluorescence light energy: preliminary findings. Vet Dermatol. 2020;31(6):460-e122. doi:10.1111/ vde.12890