Does lamotrigine cause photosensitivity? Understanding the risks and prevention

October 10, 2025 •

5 min read

While the most common and feared side effect of lamotrigine is a serious skin rash, several studies and pharmacovigilance reports have also documented that does lamotrigine cause photosensitivity, leading to exaggerated sunburn reactions and other skin issues. This occurs because the medication can make your skin more vulnerable to the sun's ultraviolet (UV) radiation.

Quick Summary

Lamotrigine can cause sun sensitivity, leading to phototoxic reactions and increased risk of sunburn. The drug absorbs UV light and generates free radicals, requiring protective measures like sunscreen and clothing to mitigate risk and prevent skin damage.

Key Points

Photosensitivity Risk: Lamotrigine can cause photosensitivity, an increased skin sensitivity to UV radiation, leading to an exaggerated sunburn-like reaction.
Phototoxic Mechanism: The medication absorbs UV light and generates reactive oxygen species, causing cellular damage and leading to phototoxic skin reactions.
Protective Measures: To prevent photosensitivity, use broad-spectrum sunscreen (SPF 30+), wear protective clothing, and limit sun exposure, especially during peak hours.
Distinguish Rash Types: It is critical to differentiate a photosensitive reaction from the more dangerous Stevens-Johnson Syndrome (SJS) rash, which is a severe systemic hypersensitivity.
Report All Rashes: Any new rash, regardless of severity, should be reported to a healthcare provider immediately to determine its cause and appropriate next steps.
Cumulative Risk: The risk of photosensitivity may be higher when lamotrigine is combined with other photosensitizing medications.

Understanding the Link Between Lamotrigine and Sun Sensitivity

Lamotrigine (brand name Lamictal) is a widely used anticonvulsant and mood-stabilizing medication prescribed for epilepsy and bipolar disorder. While it is generally well-tolerated, concerns surrounding potential skin reactions, including photosensitivity, are significant. Drug-induced photosensitivity occurs when a medication causes an adverse skin reaction in the presence of light, most often UV radiation from the sun. For individuals taking lamotrigine, this means that exposure to sunlight that would normally be well-tolerated could result in a severe skin reaction.

The Mechanisms Behind Lamotrigine Photosensitivity

Research indicates that lamotrigine can act as a photosensitizer through multiple biochemical mechanisms within the body.

Phototoxicity: This is the most common type of photosensitivity reaction caused by drugs. When UV light is absorbed by lamotrigine that has accumulated in the skin, it generates reactive oxygen species, particularly singlet oxygen. These free radicals can then cause cellular damage, leading to an exaggerated sunburn-like reaction in sun-exposed areas.
Photoallergy: A less common mechanism involves the drug undergoing a structural change due to UV radiation, a process known as photodechlorination. This altered compound can then be recognized as foreign by the immune system, triggering a delayed allergic reaction. The rash associated with a photoallergic reaction may resemble eczema and can spread to skin areas that were not exposed to the sun.
Free Radical Release: When exposed to UV radiation, lamotrigine and its photodecomposition products can release chloride anions and free radicals. This process may lead to the modification of proteins within the skin, contributing to phototoxic responses.

Types of Reactions and Key Symptoms

Photosensitivity reactions can manifest in various ways, from a mild rash to severe, blistering conditions. While a non-specific mild rash is a known side effect of lamotrigine, a photosensitive reaction is specifically triggered by sun exposure.

Symptoms of a lamotrigine-induced photosensitivity reaction typically include:

Exaggerated sunburn reaction, which can occur with less sun exposure than would normally cause a burn.
Intense redness (erythema) and burning or tingling sensations in sun-exposed skin areas.
The development of blisters or peeling in severe cases.
Itching skin rash, as reported in some case studies.

Minimizing Your Risk of Photosensitivity

For those on lamotrigine, taking proactive measures is crucial for managing sun sensitivity.

Here are some key preventative strategies:

Practice Sun Avoidance: Limit or avoid sun exposure, especially during peak hours, typically between 10 a.m. and 4 p.m.. Stay in the shade whenever possible.
Use High-SPF, Broad-Spectrum Sunscreen: Apply a broad-spectrum sunscreen with an SPF of at least 30 or higher to all exposed skin. Broad-spectrum protection guards against both UVA and UVB rays, which are implicated in photosensitivity. Reapply every two hours, or more often if sweating or swimming.
Wear Protective Clothing: Cover up with clothing made from tightly woven fabrics. Wear long sleeves, long pants, and a broad-brimmed hat to protect your face and neck.
Wear Sunglasses: Protect your eyes, as retinal phototoxicity has also been reported in patients taking lamotrigine. Choose sunglasses with UVA/UVB protection.
Avoid Tanning Beds: Steer clear of all forms of artificial UV exposure, including tanning beds.

Lamotrigine Rash: A Serious Consideration

It is vital to distinguish between a routine photosensitive reaction and the more dangerous, though rare, serious skin rashes associated with lamotrigine, such as Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN). While a photosensitive reaction is a response to light, SJS/TEN is a severe, life-threatening hypersensitivity reaction that can occur independently of sun exposure and usually develops within the first few months of treatment.


Feature	Mild Lamotrigine Rash	Serious Lamotrigine Rash (SJS/TEN)
Trigger	Can be aggravated by sunlight or occur independently of sun exposure.	A hypersensitivity reaction to the drug itself, not necessarily sun-related.
Appearance	Mild, red, itchy, sometimes patchy or bumpy rash.	Starts as red or purple, target-shaped lesions on the upper chest, palms, or soles. Can progress to widespread blistering and peeling of skin.
Systemic Symptoms	Generally localized to the skin; not associated with severe systemic illness.	Often accompanied by flu-like symptoms (fever, sore throat, malaise) before the rash appears.	Mucous Membrane Involvement	Typically does not affect mucous membranes (mouth, nose, genitals).	Frequent painful sores, blistering, and peeling inside the mouth, nose, eyes, and genitals.
Required Action	Contact your healthcare provider immediately for evaluation. They may decide to lower the dose, stop the medication, or use antihistamines.	Seek emergency medical attention immediately. Discontinuation of lamotrigine is typically required.

Conclusion: Navigating Treatment and Sun Exposure

While does lamotrigine cause photosensitivity is a real concern for patients, it is important to remember that this side effect is manageable. By understanding the risk, taking diligent preventative measures like sun avoidance and proper sunscreen application, and recognizing the signs of a serious skin reaction, individuals can continue their treatment safely. Maintaining open communication with your healthcare provider is paramount; any new rash or skin changes should be reported immediately, regardless of apparent severity. For additional information on medication-induced photosensitivity, you can consult resources like the NIH website.

Potential for other medications

It is also worth noting that many other medications can cause photosensitivity. If you are taking lamotrigine and other drugs, your risk may be higher. Other common photosensitizers include:

Certain antibiotics, like tetracyclines and fluoroquinolones
Diuretics, such as hydrochlorothiazide
Nonsteroidal anti-inflammatory drugs (NSAIDs), like naproxen
Some antidepressants, especially tricyclics
Certain antifungals, like voriconazole

Your healthcare provider can review all your medications to determine your overall risk of photosensitivity. If discontinuing the medication is not possible, strict adherence to sun protection is key.

What to do in case of a reaction

If you experience a photosensitive reaction while on lamotrigine, several steps can be taken to manage the symptoms. For mild reactions, avoiding further sun exposure, applying cool compresses, and using moisturizers can help. Topical corticosteroids may be used to reduce inflammation. However, if the reaction is moderate or severe, or if blistering occurs, prompt medical attention is necessary. In these severe cases, discontinuing lamotrigine may be required under a doctor's supervision. Always consult your physician before making any changes to your medication regimen. The treatment path depends entirely on the severity of the reaction and its underlying cause.

Frequently Asked Questions

Yes, taking lamotrigine can make you more susceptible to severe or exaggerated sunburns, even with less sun exposure than you might normally experience. This is due to the drug's photosensitizing properties, which increase your skin's vulnerability to UV light.

Photosensitivity reactions can occur at any time while you are taking lamotrigine, though skin-related side effects like rashes are most common within the first few weeks of starting the medication or increasing the dose. Consistent sun protection is recommended throughout your treatment.

Not everyone taking lamotrigine will experience photosensitivity. Individual reactions vary based on factors like genetics, skin type, co-medications, and the rate of dose increase. However, because the risk exists for anyone on the medication, proper precautions should be taken.

You should use a broad-spectrum sunscreen with an SPF of 30 or higher. A broad-spectrum formula protects against both UVA and UVB rays. Sunscreens containing ingredients like zinc oxide and titanium dioxide are particularly effective at blocking the UVA radiation that often triggers drug-induced photosensitivity.

Yes, you can still go outside, but you should take precautions. Minimize your sun exposure during peak hours (10 a.m. to 4 p.m.), seek shade, wear protective clothing, and apply high-SPF, broad-spectrum sunscreen.

Serious skin reactions like Stevens-Johnson Syndrome (SJS) often begin with flu-like symptoms (fever, sore throat) followed by a painful, spreading rash. This rash can blister and lead to peeling skin, with painful sores appearing in the mouth, eyes, or genital area. Any of these symptoms require immediate medical attention.

For most individuals, photosensitivity resolves upon discontinuation of the causative medication, though some post-inflammatory hyperpigmentation may persist. However, you should never stop taking lamotrigine without consulting your doctor, as abrupt cessation can cause other serious side effects, such as seizures.