Vitamins That Cause Sun Sensitivity

Overview

For some people, sunbathing, or ‘sun worshipping’, is a relaxing way to spend their holidays. Furthermore, for some of us, it is literally addictive and can have the same effects on our bodies as some illicit drugs thanks to the increase in those wonderful hormones we all love: endorphins. It is therefore understandable why scientists are trying to educate us to respect the sun and its possible negative health effects, such as sunburn and accelerated ageing.¹

It is not only sunbathing which can cause damage to our skin, but also the use of some medicines, vitamins, and minerals can increase the damaging effects of the sun to our skin. This phenomenon is called photosensitivity.² This condition may be something that your doctor has already talked to you about after prescribing you a specific medicine, or it may be something that you have been diagnosed with i.e. sun allergy. 

Sunlight and vitamin D

Today the benefits of vitamin D have been widely discussed in the media. The ‘sunshine’ vitamin, more commonly known as Vitamin D, is a special vitamin, as it can be made in your skin by sunlight. Across the world, vitamin D insufficiency affects 50% of the population. This can be attributed to lifestyle choices (less outdoor activities) and environmental factors (air pollution). High incidences of people being deficient in this vitamin is a public health concern as it is needed to prevent chronic diseases.³ Deficiency is common across all age groups as this vitamin is not easily found in foods. 

Research has shown that vitamin D is important against the following diseases:

• Cancer
• Heart disease
• Fractures and falls
• Autoimmune diseases
• Influenza
• Type 2 diabetes 
• Depression 

Vitamin D exists in two forms: Vitamin D2 and Vitamin D3. Vitamin D3 is made in your skin by the sun and Vitamin D2 is present in certain oily fish, such as salmon, mackerel, or herring. 

As our 21st century lifestyles involve indoor activities and the use of sunscreen, it is recommended that many people take a Vitamin D supplement.³ This can be discussed with your doctor or local pharmacist. 

Signs of sun sensitivity

The major signs of sun sensitivity are a rash or symptoms similar to sunburn, such as sore, red skin. The rash may or may not cause itching and in extreme cases it can cause blistering. Weeping and peeling of the skin can also occur in extreme cases.²

The main areas of your skin affected by photosensitivity are those most commonly exposed to light, such as your face, back of your neck, font of your leg, and the tops of your hands.⁴ 

There are two kinds of sun sensitivity reaction - photoallergic and phototoxic.

Phototoxic reaction- this is the most common reaction and usually happens when you are taking a medicine that can be activated by sunlight. Consequently, this causes damage to the skin and the symptoms can arise within minutes or hours after exposure. This reaction can occur with topical application of the medicine or when you take it by mouth.^2,4 

Photoallergic reaction - this is less common and happens when the UV rays from sunlight interact with some of the chemicals in medicines you have taken or put on your skin. Your immune system then thinks that these changes are a threat to your body. The immune system then starts to produce antibodies and attacks the chemicals, in turn causing an immune response or a reaction. It is this reaction that can cause the red, swollen, blistered, and weeping skin as mentioned previously.^2,4 

So why are these reactions important? 

Photosensitivity puts pressure on your skin's natural defences and increases the risk to your skin of being damaged by the sun's harmful rays.

Exposure to medicines causing photosensitivity reactions has also been related to the development of skin cancer.⁶ The direct relationship is still being discussed by scientists and the exact reasons why photosensitivity causes cancer are still not clear. However, certain factors are thought to contribute to the risk, such as age, cumulative dose, and length of treatment. 

Vitamins that can cause sun sensitivity

Vitamin B6

Vitamin B6 is a vitamin that is soluble in water and that your body needs for many different functions.⁷ Some of its functions are:

• Improve mood and reduced risk of depression 
• May promote brain health 

Although not common, some evidence has shown that vitamin B6 may cause photosensitivity. 

The findings were not in vivo (in a live human body) but rather in vitro (human cell cultures), therefore more research is needed in this area. However, if you do experience any photosensitivity reactions when taking vitamin supplements, it is important to check if vitamin B6 is an ingredient - it is also known as pyridoxine.⁸ If you have any concerns around taking this vitamin then speak to your GP for further information. 

Vitamin A

Vitamin A is essential in maintaining your health, and as it cannot be formulated in the body, you need to get it from your diet. It plays an important role in maintaining your vision, immune system, both male and female fertility as well as foetal growth and placenta development.⁹

The form of vitamin A that the body absorbs most readily can be found in the following foods:

• Salmon
• Egg yolks
• Beef liver
• Trout
• Cheddar cheese

Other foods that are high in beta carotene, the form of Vitamin A that is dependent on factors such as genetics for metabolism and absorption, are: 

• Sweet potato
• Carrot
• Pumpkin
• Papaya
• Red peppers

It is harder for the body to absorb vitamin A from these sources than from the animal sources mentioned above. 

Vitamin A is also another name for the group of compounds that are soluble in fat known as retinoids. You may find this name familiar if you have ever used retinol as part of a beauty regime. Retinoids, such as tretinoin and isotretinoin, are known to cause photosensitivity reactions when used orally or topically.¹⁰ It is therefore important that you protect your skin when consuming vitamin A or its derivatives and spending prolonged periods in the sun. If you have any doubts about taking this medicine it is important to consult your doctor. 

1. John’s Wort

St John's wort is a plant that has been used in herbal medicine to treat ailments for centuries. One of its main uses is for depression. There has been a lot of research carried out into st. John's wort for the treatment of depression and it has shown to be more beneficial than placebo. 

It may also cause photosensitivity, especially in high doses.¹¹ It is possible that a topical application may also increase your skin's sensitivity to the sun, however there is not enough evidence to prove this at the moment. 

Other common causes of sun sensitivity

Vitamins are only one example of the plethora of medicines that can cause photosensitive reactions. 

Antibiotics

There are a number of different antibiotics which can induce photosensitive reactions, the most commonly seen in practice are:²

• Ciprofloxacin- used to treat urinary infections

• Tetracycline- used to treat skin infections, commonly acne

• Co-Trimoxazole- used to treat urinary infections and respiratory infections 

• Dapsone- also used to treat skin infections, in a combination with other drugs in treating leprosy

Acne treatment

Tetracyclines are a class of antibiotics commonly used to treat skin conditions. They have been used to treat acne and pelvic infections for over 50 years.¹² They are known to cause photosensitivity, with doxycycline being the biggest offender and minocycline causing the least photosensitivity.⁵ 

Isotretinoin is another medicine used in the treatment of acne, often when the acne involves deep, painful cysts and when it hasn’t been helped by other medicines. It belongs to the retinoids, a group of compounds that can be derived from Vitamin A. The epidermis, the outermost layer of the skin, and the dermis,the second layer of skin, respond well to retinoids. It can be used both orally and topically.¹³ 

Evidence has shown that isotretinoin causes photosensitivity and that it is really important to protect your skin from the sun when taking this medicine.¹⁴ 

Allergy medications 

Antihistamines are medicines you may have taken if you have ever experienced allergies, such as hay fever or allergy to pets. Benadryl or diphenhydramine, which is a commonly used OTC (over the counter) antihistamine can cause heat sensitivity.¹⁴ This is not the same as photosensitivity. 

As this medicine can reduce your ability to sweat, this therefore limits your body's ability to cool down. Too much sun exposure while taking this medicine can cause you to overheat as you may not realise how hot you are getting.¹⁴ Although this is not classed as a common side effect, in extreme cases it can cause cramps and exhaustion. It is important to be aware of the amount of time you spend in the sun when taking Benadryl, or speak to a pharmacist or doctor for alternatives.

Antidepressants

Some antidepressants medicines that cause phototoxic reactions are (6):

• Amitriptyline 

• Imipramine 

• Venlafaxine

When starting on new medicines, such as those above, it is important to consult with your GP regarding the side effects. 

Chlorpromazine - Although not an antidepressant, it is active in the central nervous system. Chlorpromazine is an antipsychotic antihistamine that is known to cause photosensitivity. It is commonly used to treat schizophrenia and psychoses. If you are taking this medicine, care should be taken to protect your skin from the sun.¹⁵ 

Protecting your skin from the sun 

According to Cancer Research UK, skin cancer rates have increased in both male and females in the age range of 25-80 years over the last ten years. It is now the 5th most common cancer in the UK.¹⁶ 

In The USA, The American Academy of Dermatology encourages you to #practicesafesun whenever you are outdoors.¹⁷ This is for a number of reasons:

• Skin cancer is the most common cancer in the United States
• People of all skin tones get skin cancer
• Skin cancer is one of the most preventable cancers
• When you protect your skin from the sun it reduces the risk of developing skin cancer

So how do you then #practicesafesun?^16,17

• Seek shade between 10am and 2pm, as this is when the sun’s rays are the strongest

• Sun protective clothing- including glasses with UV protection, a wide-brimmed hat, a lightweight long-sleeve shirt. For even more protection, choose clothes with a UVF number on the label

• Apply sunscreen- do not rely on sunscreen alone to protect you from the sun. The label should have an SPF number of at least 30 to protect against UVB rays. UVA protection can usually be seen in a circle with “UVA” inside. It should not be past its expiry date. Apply the appropriate amount of sunscreen - if it is applied too thinly then it reduces the amount of protection it gives. See the NHS link for further details.¹⁸

In general, if you are using any vitamins or medicines that can cause photosensitivity then it is important you protect your skin from the sun. It is best to stay out of the sun, especially in the hottest hours. If you require further advice on sunbathing while on photosensitive medicines then consult your GP.