Why would my skin suddenly burn faster than it used to?
Because something you take, or put on your skin, can absorb light and turn it into damage. Dermatology calls this photosensitivity. It is a recognized reaction to medicines, not something you imagined. Evidence Evidence
Why this matters
A medicine, or what your body breaks it down into, sits in the skin and absorbs ultraviolet or visible light. That sets off a chemical reaction in the skin itself. DermNet puts this at up to 8% of reported drug skin reactions, and says the real figure is probably higher because it goes unreported.
Questions for whoever prescribes for you
- Could anything I take be making my skin burn faster?Saving keeps this on your device and needs JavaScript, which is off in this browser.
- Do you want to hear about it if my skin reacts after a treatment?Saving keeps this on your device and needs JavaScript, which is off in this browser.
Is there more than one kind of reaction?
There are two, and they do not look or behave alike. The common one is not an allergy at all, and it arrives fast. The other is an allergy to the light-changed medicine, and it arrives late. Evidence Evidence
Why this matters
DermNet describes the fast form appearing within minutes to hours on skin the light reached. It looks like a sunburn that went too far, with redness, swelling, burning and stinging. The allergic form appears 24 to 72 hours after light, more like an itchy eczema rash, and it can spread past the skin the light touched. The FDA describes the same split, and calls the fast one more common.
Questions for whoever prescribes for you
- Does the pattern of this rash tell you which kind it is?Saving keeps this on your device and needs JavaScript, which is off in this browser.
- Would a photo of the reaction be useful before it fades?Saving keeps this on your device and needs JavaScript, which is off in this browser.
Which medicines and products are on the published lists?
More than most people expect. Antibiotics are the famous ones. The published lists also carry antifungals, anti-inflammatory painkillers, water tablets, heart medicines, retinoids, some diabetes tablets and St John’s wort. Things you put on your skin are on there too. Evidence Evidence
Why this matters
The FDA groups its own list like this.
- Antibiotics, antifungals and sulfonamides.
- Diuretics, heart medicines and cholesterol medicines.
- Anti-inflammatory painkillers, such as ibuprofen and naproxen.
- Retinoids, phenothiazines and sulfonylureas for type 2 diabetes.
- Antihistamines, oral contraceptives and estrogens.
- Psoralens, and alpha hydroxy acids in cosmetics.
Questions for whoever prescribes for you
- Does anything on my list change how easily I burn?Saving keeps this on your device and needs JavaScript, which is off in this browser.
- If another doctor starts me on something, who should I tell?Saving keeps this on your device and needs JavaScript, which is off in this browser.
Is it only medicines? What about food and plants?
No, and this is the part nobody tells you. Juice and sap from certain plants do the same thing. Lime is the famous one. Get it on your hands making drinks, then go out in the sun, and the skin can blister a day or two later. Evidence
Why this matters
DermNet calls this phytophotodermatitis. The plants carry chemicals called furanocoumarins. Ultraviolet A light reacts with them in the skin and causes damage and inflammation. It is a direct chemical effect, not an allergy, and the immune system is not involved. Its table names Queen Anne’s lace, cow parsnip, giant hogweed, parsnip, celery, lime, the gas plant and fig sap. The skin turns red about 24 to 48 hours after the light and often blisters. The marks come as streaks, or as drip shapes running down an arm.
Questions for whoever prescribes for you
- I got a burn from a plant or a fruit. Do you want to see it?Saving keeps this on your device and needs JavaScript, which is off in this browser.
- Does this change anything about the treatment I am on?Saving keeps this on your device and needs JavaScript, which is off in this browser.
What has any of this got to do with PUVA?
PUVA is the same chemistry, done on purpose. Those plant chemicals have a medical name: psoralens. A clinician gives one, then gives ultraviolet A light. The difference between a treatment and a burn is who is controlling the light. Evidence Evidence
Why this matters
DermNet groups furocoumarins and psoralens together in its table, and names PUVA as what they are used for. It gives methoxsalen, 5-methoxypsoralen, trioxsalen and psoralens put on the skin. It also says these properties are sometimes used on purpose in treatment. The FDA lists psoralens among the medicines that raise sun sensitivity, naming methoxsalen and trioxsalen.
Questions for whoever prescribes for you
- Which light source is being proposed for me, and why that one?Saving keeps this on your device and needs JavaScript, which is off in this browser.
- If a psoralen is part of my plan, what should I watch for outdoors?Saving keeps this on your device and needs JavaScript, which is off in this browser.
So what do I actually do with this?
Take it to whoever prescribes for you, and say the part that is easy to leave out: you are getting ultraviolet light on purpose. The doctor who wrote your antibiotic may have no idea there is a panel in your bedroom. Do not stop anything on your own. Evidence
Why this matters
The FDA says questions about your medicines and the possibility of a reaction belong with a health professional or a pharmacist. Its list counts what you put on your skin, not only what you swallow. The medicine review a phototherapy service runs is set out on our NB-UVB safety page.
Questions for whoever prescribes for you
- Does anything I take need checking against my light treatment?Saving keeps this on your device and needs JavaScript, which is off in this browser.
- Can I have your answer in writing to show the other prescriber?Saving keeps this on your device and needs JavaScript, which is off in this browser.
Evidence and update context
This optional layer shows the evidence boundary reviewed for this page as of 2026-08-21.
- What this evidence supports
- A medicine, or what your body breaks it down into, sits in the skin and absorbs ultraviolet or visible light. That sets off a chemical reaction in the skin itself. DermNet puts this at up to 8% of reported drug skin reactions, and says the real figure is probably higher because it goes unreported.
- What it does not establish
- The FDA says plainly that not everyone who takes these products reacts. It also says that reacting once does not mean you will react the next time. Neither source can tell you whether the thing you take will do this to you.
Evidence behind this page
Sources
Each evidence badge opens the source and its limits. The full list stays available here.
- U.S. Food and Drug AdministrationRegulatory · Regulatory / guideline, tier 1Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports that selected medicines and skin products can cause photosensitivity. Questions about a person’s medicines belong with a health professional or pharmacist. It names two forms. Photoallergy is an allergic reaction of the skin. It may not appear until several days after sun exposure. Phototoxicity is more common, and is an irritation that can occur within a few hours. Both follow ultraviolet light, from the sun or from a lamp. Its named groups are antibiotics, antifungals, antihistamines, diuretics and retinoids. It also names cholesterol medicines, anti-inflammatory painkillers, oral contraceptives and estrogens. It names phenothiazines, sulfonamides and sulfonylureas for type 2 diabetes. It names psoralens, giving methoxsalen and trioxsalen. It names alpha hydroxy acids in cosmetics.
What it does not support
It does not show that every listed medicine causes a reaction. It does not diagnose an unexpected skin change. It does not reconcile a medicine warning with clinician-directed phototherapy. It says plainly that not all people who take these medicines will react. It says that reacting once does not guarantee reacting the next time. Its list is not offered as a complete one. It names no product this site has checked against a reader’s own prescription. Its sun-protection paragraph is guidance this site reports rather than issues.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- DermNet (Lau LDW, Vu M, Scardamaglia L; reviewing dermatologist Coulson I; previous contributor Ngan V)Patient education · Patient education, tier 5Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports that a medicine, or what the body breaks it down into, can sit in the skin. There it absorbs ultraviolet or visible light and sets off a reaction. There are two forms. The phototoxic one is more common, and the immune system is not involved. It appears within minutes to hours on skin the light reached. It looks like a sunburn that went too far, with redness, swelling, burning and stinging. The photoallergic one is an immune reaction. It appears 24 to 72 hours after light, as an itchy rash like eczema. It can spread beyond the skin the light reached. Its table names antibiotics, antifungals, heart and water tablets, and anti-inflammatory painkillers. The same table names oral retinoids, phenothiazines, sulfonylureas and St John’s wort. It also names fragrances, some sunscreen ingredients and some wound cleansers. It groups furocoumarins and psoralens together as what PUVA uses. It gives methoxsalen, 5-methoxypsoralen, trioxsalen and psoralens put on the skin. It supports that these properties are sometimes used on purpose in treatment. It puts this reaction at up to 8% of reported drug skin reactions.
What it does not support
It is a dermatology reference page, not a trial. It sets no frequency for any one medicine and no result for any one person. It reports that the phototoxic form is seen more often in people with lighter skin, and puts that down to melanin. It measures nothing about skin where pigment has been lost, so it supports no statement about depigmented patches. It says its own 8% figure is likely under-diagnosed and under-reported. Nothing on it is used here to identify a rash. Nothing on it is used to weigh a reaction against the reason a medicine was prescribed. Nothing on it supports stopping or changing any medicine.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- DermNet (Coulson I, Consultant Dermatologist, East Lancashire NHS Trust; copy edited by Mitchell G)Patient education · Patient education, tier 5Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports that sap and juice from some plants carry natural photosensitizing chemicals called furanocoumarins. Ultraviolet A light reacts with them in the skin and causes damage and inflammation. The reaction is a direct toxic effect, and the immune system is not involved. Its table names Queen Anne’s lace, cow parsnip, giant hogweed, parsnip and celery. The same table names lime, the gas plant, and fig from the sap rather than the fruit. About 24 to 48 hours after the light, the smeared skin turns red, swells and often blisters. The marks can be streaks, or drip shapes down an arm from lime juice. They can appear on the face and hands after eating large amounts of these foods. Eating them in quantity causes a more widespread version of the same thing. Healing leaves a pigment change that may last for several years. That pigment change may be more intense in skin of color.
What it does not support
It does not identify a rash on a reader or rule out another cause. It does not say how likely any one exposure is to cause a reaction. It names no amount of any food. It establishes nothing about vitiligo, because it never mentions the condition. It measures nothing about skin where pigment has been lost. Its treatment section is deliberately not used here. A website may not direct the care of a skin reaction.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.