Can red light therapy worsen skin conditions?

For the vast majority of skin conditions, including acne, psoriasis, eczema, and rosacea, red light therapy is beneficial and often prescribed to reduce flare-ups, promote healing, and improve skin texture. Its ability to reduce inflammation and stimulate collagen production makes it a versatile dermatological tool. However, there are specific scenarios where RLT could potentially worsen a condition. The primary concern lies in active skin cancers or pre-cancerous lesions (like actinic keratosis). Since RLT stimulates cellular metabolism and proliferation, there is a theoretical risk that it could accelerate the growth of malignant or pre-malignant cells. Therefore, RLT should never be applied directly over known or suspected skin cancers without explicit oncologist approval.

Another potential issue arises with hyperpigmentation in darker skin types if the device emits significant heat alongside the light. While pure LED RLT is "cool," some lower-quality devices or those combining RLT with heating elements could induce post-inflammatory hyperpigmentation (PIH) in susceptible individuals if the skin overheats. Additionally, individuals with lupus erythematosus or other photosensitive autoimmune diseases might experience flare-ups due to light exposure, although this is more commonly associated with UV light. The reaction to visible red light in these patients varies, so a patch test and medical consultation are crucial. Lastly, applying RLT over active, infected wounds without proper cleaning could theoretically trap bacteria if the heat promotes a breeding environment, though RLT itself has antimicrobial properties. In summary, while RLT improves most skin conditions, it must be avoided over malignancies and used with caution in photosensitive autoimmune disorders.