How does ringworm look on a cat under ultraviolet light? - briefly
When viewed under ultraviolet light, ringworm on a cat appears as bright green or fluorescent spots. This is due to the presence of porphyrins in the fungal cells, which react with the UV light.
How does ringworm look on a cat under ultraviolet light? - in detail
Ringworm, also known as dermatophytosis, is a common fungal infection that affects cats. When diagnosed under ultraviolet (UV) light, specific characteristics become visible, aiding in accurate identification and treatment.
Under normal light conditions, ringworm may appear as circular or irregular patches of hair loss on the cat's skin. These areas can be red, inflamed, or scaly, often accompanied by broken hairs. However, these symptoms are not unique to ringworm and could also indicate other skin conditions.
When examined under UV light, typically a Wood's lamp with a wavelength of 365 nanometers, the fungi responsible for ringworm emit a distinctive fluorescent glow. This glow is due to the presence of psoralens, naturally occurring compounds in the fungus that react to UV light. The affected areas will appear bright green or yellow under the Wood's lamp, making the infection more readily apparent and distinguishable from other skin issues.
It is essential to note that not all strains of ringworm fluoresce under UV light. Some species, such as Microsporum canis, are known for their strong fluorescence, while others like Trichophyton mentagrophytes may not exhibit any visible glow. Therefore, a negative result under the Wood's lamp does not rule out ringworm entirely and should be followed up with additional diagnostic tests, such as fungal culture or polymerase chain reaction (PCR) analysis.
In summary, examining a cat for ringworm under UV light can provide valuable visual information that supports a timely and accurate diagnosis. However, it is crucial to remember that this method has limitations and should be used in conjunction with other diagnostic tools for comprehensive assessment.