Phototherapy burns are essentially UV burns, similar to a sunburn, caused by overexposure during light therapy sessions. Most mild cases heal on their own within a few days with proper home care: cool the skin, moisturize, and protect the area from further UV exposure. More severe burns with blistering or persistent pain need medical attention and will change how your next treatment sessions are managed.
Cool and Moisturize in the First 24 Hours
The first step is bringing down the heat and inflammation in your skin. Apply cool (not ice-cold) compresses to the affected area for 15 to 20 minutes at a time. You can repeat this several times throughout the day. Avoid placing ice directly on the burn, which can damage already-irritated skin.
Once the skin has cooled, apply a fragrance-free moisturizing lotion to keep it supple and relieve itching or burning. Reapply throughout the day, especially after bathing. Aloe vera gel is another option that many people find soothing, though any gentle, unscented moisturizer works. Stay hydrated by drinking extra water, just as you would with a regular sunburn.
If your eyes are watery or irritated from the session, cold compresses over closed eyelids, artificial tears, or eye patches can help. Wear sunglasses for the first 24 hours after treatment, even indoors near bright windows.
What About Steroid Creams?
Topical corticosteroids are commonly recommended as first-line treatment for UV burns, but the evidence for their effectiveness after the burn has already developed is surprisingly weak. A randomized, double-blind trial published in JAMA Dermatology tested both moderate-potency and high-potency steroid creams applied 6 or 23 hours after UVB exposure. Neither strength produced a clinically meaningful reduction in redness or inflammation at those time points.
The only scenario where a steroid cream made a real difference was when a high-potency formulation was applied 30 minutes before UV exposure, which isn’t useful once you already have a burn. An earlier study suggested that applying a moderate-potency steroid twice daily starting 6 hours after exposure might slightly speed recovery by days 4 and 5, but the effect was modest.
In practical terms, an over-the-counter hydrocortisone cream is unlikely to hurt and may take the edge off itching, but don’t expect it to dramatically shorten healing time. For significant burns, your dermatologist may prescribe something stronger. Over-the-counter pain relievers like ibuprofen can help manage discomfort and reduce some of the inflammatory response, especially in the first day or two.
Handling Blisters
Blistering from phototherapy is uncommon but does happen, particularly with narrowband UVB treatments. If blisters form, resist the urge to pop or drain them. The intact blister acts as a natural sterile dressing that protects the raw skin underneath from bacteria.
Cover blistered areas loosely with a non-stick bandage or gauze to prevent friction from clothing. If a blister breaks on its own, gently clean the area with mild soap and water, apply a thin layer of petroleum jelly or antibiotic ointment, and cover it with a clean bandage. Change the dressing daily or whenever it gets wet or dirty.
How Long Recovery Takes
Mild phototherapy burns (pink skin, slight tenderness) typically resolve within 2 to 4 days. Moderate burns with noticeable redness and discomfort can take a week or more to fully settle, often progressing through a peeling phase similar to a healing sunburn. During peeling, continue moisturizing and avoid picking at flaking skin.
Some people notice darker patches (hyperpigmentation) in the burned areas after healing. This is more common in darker skin tones and usually fades over several weeks to months, though it can occasionally persist longer. Keeping the area protected from additional sun exposure helps prevent the discoloration from deepening.
Restarting Phototherapy After a Burn
You should not return for your next phototherapy session while your skin is still red or painful. Clinical protocols from major phototherapy centers call for waiting until the burn fully resolves, then restarting at a dose reduced by about 15%. This lower dose helps prevent a repeat burn while your skin recovers its tolerance. Your treatment team will then increase the dose more gradually from that new baseline.
Let your phototherapy provider know about the burn before your next appointment, even if it has healed. They need that information to recalibrate your dosing schedule. Burns during phototherapy are a signal that the dose was too high or increased too quickly, and adjustments prevent it from happening again.
Signs That Need Medical Attention
Most phototherapy burns are mild and manageable at home, but certain symptoms indicate you need to contact your provider promptly:
- Burning that persists beyond 24 hours after treatment, especially if it’s getting worse rather than better
- Blistering over a significant area of skin
- Flu-like symptoms such as fever, chills, nausea, or vomiting after a session
- Signs of infection in any blistered or broken skin, including increasing redness, swelling, warmth, pus, or a wound that won’t heal
- New vision problems that weren’t present before treatment
Phototherapy can also reactivate herpes simplex (cold sores) in the treated area. If you notice the telltale tingling or clustered blisters, contact your provider, as antiviral treatment works best when started early.