Welcome to CatForum and I hope we can help.

Wiki says:

http://en.wikipedia.org/wiki/Ultraviolet
While "black lights" do produce light in the UV range, their spectrum is confined to the longwave UVA region. Unlike UVB and UVC, which are responsible for the direct DNA damage that leads to skin cancer, black light is limited to lower energy, longer waves and does not cause sunburn. However, UVA is capable of causing damage to collagen fibers and destroying vitamin A in skin.

It appears that blacklights are basically harmless in 'low doses'. To me, I interpret low doses to mean under several hours exposure.
What you describe on your kitty, with the circular hairloss and hairshaft discoloration, it sounds like a fungal issue; ringworm, whose presence is detected with the use of a Woods/Black-light.


Wiki:

http://en.wikipedia.org/wiki/Ringworm
Diagnosis in pets
Ringworm in pets may often be asymptomatic, resulting in a carrier condition which either infects other pets, or shows disease only when the companion animal develops an immunosuppressive condition. Circular bare patches on the skin suggest the diagnosis but no lesion is truly specific to the fungus. Three species of fungi cause 95% of ringworm in pets. These are Microsporum canis, Microsporum gypseum, and Trichophyton mentagrophytes.

Veterinarians have several tests to identify ringworm infection and identify species:

Woods Test: This is a black light (ultraviolet light) with a magnifying lens. Only 50% of Microsporum canis will show up as an apple-green fluorescence on hair shafts, under the black light. The other fungi do not show. The fluorescent material is not the fungus itself (which does not fluoresce) but rather an excretory product of the fungus which sticks to hairs. Infected skin does not fluoresce.

Microscopic test: The vet takes hairs from around the infected area and places them in a staining solution to view under the microscope. Fungal spores may be viewed directly on hair shafts. This technique identifies a fungal infection in about 40%-70% of the infections but cannot identify the species of dermatophyte.

Culture Test: This is the most effective but also the most time-consuming way to determine if there is ringworm on a pet. In this test, the veterinarian collects hairs from the pet, or else collects fungal spores from the pet's hair with a toothbrush, or other instrument, and inoculates fungal media for culture. These cultures can be brushed with transparent tape and then read by the vet using a microscope, or can be sent to a pathological lab. The three common types of fungi which commonly cause pet ringworm can be identified by their characteristic spores. These are different-appearing macroconidia in the two common species of Microspora, and typical microconidia in Trichophyton infections.

Identifying the species of fungi involved in pet infections can be helpful in controlling the source of infection. Microsporum canis, despite its name, occurs more commonly in domestic cats, and 98% of cat infections are with this organism. It can also infect dogs and humans, however. Trichophyton mentagrophytes has a major reservoir in rodents, but can also infect dogs and horses. Microsporum gypseum is a soil organism and is often contracted from gardens and other such places. Besides humans, it may infects rodents, dogs, cats, horses, cattle, and swine.

Ringworm on a human arm:

Small-ish and large-ish spots on shaved cats:

Larger spots on dogs:

 

Yeah, I VERY much doubt that there is any connection to the UV light.

 

I am now wondering what that light was exactly, if the hair will grow back, and if that thing could have caused permanent damage to my cat's skin, if it can cause other problems, etc. Any information you have about this light, the device vets have and the safety guidelines that they must follow when using it and the dangers of using it will help me.

I want to be perfectly clear:
The vet's use of a woods/black-light did not cause the hairloss on your cat. (because of what you described) Your cat's hairloss is caused by the fungal infection known as ringworm. If you are angling for information that would put your vet and her use of the w/b-light at fault, you will not get it here. Anyone who tells you that *was* the cause of the hairloss is ignorant about the use of a w/b-light in diagnosis and incorrect about the w/b-light being the cause of the hairloss. RINGWORM.

 

Yup. Sounds like ringworm.
Woods/black lights are used all the time and I have never heard of any skin damage from one.
If it is ringworm, it needs to be treated asap as it will get worse and get harder to treat. It can also spread to other pets and humans so take care of it right away. If you're not happy with your vet, go to another one. Good luck.

 

totally the ringworm topic but had to interject here.

If w/b lights caused hair loos in cats both of mine would be bald from me using my black light to clean up urine, coffee and I don't want to know what they are stains on my carpet.

The light your doc used did NOT cause the skin issue, repeat DID NOT.

 

People get some very odd ideas sometimes.

If UV light cause people to go bald, every single clubber from the 80's would require toupes

I don't know what it is (Heidi's probably right), but it's not the light.

 

People get some very odd ideas sometimes.

If UV light cause people to go bald, every single clubber from the 80's would require toupes

I don't know what it is (Heidi's probably right), but it's not the light.

id be bald and blind by now.