It is sometimes referred to as being allergic to the sun.
There are many causes of photosensitivity, such as reactions to certain medications and underlying health conditions.
One such condition iserythropoietic protoporphyria(EPP), which is a rare genetic disorder.
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People with EPP experience a range of photosensitivity, from mild discomfort to severe pain.
People with EPP have decreased activity of an enzyme calledferrochelatasein their red blood cells.
This leads to a buildup of a protein calledprotoporphyrinthat can make their skin very sensitive to sunlight.
Less frequently, those with EPP have mutations in a different gene, ALAS2.
This condition is calledX-linked protoporphyria(XLP), and can only be passed to children by the mother.
The mutations in the FECH gene are passed down in anautosomal recessivepattern.
This means that one parent has a very strong mutation and the other has a weaker one.
If a child receives both mutations, the stronger mutation dominates the weaker one and they will develop symptoms.
Because EPP is a rare condition, it can be difficult to diagnose.
Enzyme Deficiency and Skin Health
There are eight different enzymes involved in makingheme.
Mutations to the FECH gene inhibit the activity of an enzyme called ferrochelatase needed to make heme.
The buildup of protoporphyrin in the skin can cause intense sensitivity to sunlight, also known asphotosensitivity.
This can significantly impact everyday life.
Symptoms of Photosensitivity
The most common symptom of EPP is photosensitivity.
Warning signs upon exposure include tingling, itching, and burning of the skin.
Longer sun exposure can lead to increasing pain.
The pain usually subsides within 24 hours.
If you are avoiding sunlight because of such discomfort, it is best to speak with a healthcare professional.
Children
While symptoms usually start in childhood, EPP is not always diagnosed right away.
However, if these symptoms are consistently present upon being exposed to sunlight, talk to a healthcare professional.
This would help them diagnose EPP.
Experienced biochemistry labs can usually distinguish EPP from XLP based on the key in of protoporphyrins in the blood.
How EPP Is Treated
Sun protection is vital for people with EPP.
It is the main form of treatment for managing EPP.
Some artificial lights, like fluorescent lights, may also need to be avoided to manage EPP flare-ups.
Medication is also available to treat EPP.
Adapting to Sun Sensitivity
Being extremely sensitive to the sun impacts everyday life.
While there is no cure for EPP yet, it is treatable.
Drugs like Scenesse can significantly help someone living with EPP.
However, it may not be accessible to everyone with EPP.
It is associated with the condition EPP and can cause mild to severe pain upon sun exposure.
Managing photosensitivity from EPP includes lifestyle changes, medication, and supplements.
A Word From Verywell
While EPP is not yet curable, photosensitivity from EPP is manageable.
But management is an everyday task and being on constant alert for possible sun exposure can affect mental health.
It can help to remember that you are never alone in your struggle.
Photosensitivity can range from mild to severe.
Upon exposure to the sun, signs of photosensitivity include tingling, itching, and burning of the skin.
Longer sun exposure can lead to increasing pain, but it usually goes away within 24 hours.
National Organization for Rare Disorders.Erythropoietic protoporphyria and X-linked protoporphyria.
Porphyria Foundation.Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP).
National Institute of Health.Autosomal erythropoietic protoporphyria.
2019;8(8):259. doi:10.3390/antiox8080259
MedlinePlus.Porphyria.
