What Is Photosensitivity?

By jolene

Article Sources

Medical Expert

More About Us

Photosensitivity refers to the amount of reactivity an object has when it receives photons, especially in situations when there is visible light. In medicine, photosensitivity is a term used to describe abnormal reactions the skin has when there is light. It can be divided into photoallergy and phototoxicity.

Photosensitivity has been observed in both humans and animals. In humans, it can take various forms. Some are more sensitive while in others, it is due to a side effect of medications (such as tetracycline antibiotics, sulfonamides, and heart drugs like amiodarone). There are also dietary supplements that can lead to photosensitivity. Some conditions such as porphyria, systemic lupus erythematosus, and xeroderma pigmentosum are also more sensitive to light. In animals, photosensitivity has been observed in horses, bovine, and sheep. It can be due to ingestion of plants such as St John’s wort, buckwheat plants (horses), and biserrula (in sheep).

1. Photoallergy

Photoallergy, photodermatitis, or sun poisoning is a form of photosensitivity. It occurs when the allergen is activated by light to result in an allergic response such as a rash or other effects. It can cause issues such as burning sensation, swelling, itchy rash where there is peeling of the skin, and difficulty breathing. Some patients may also experience nausea. In the affected areas, a brown or orangish tint may form. Photoallergy may be caused by various medications (such as nonsteroidal anti-inflammatory drugs, retinoids, oxybenzone, psoralens, tetracycline antibiotics), and plants (such as giant hogweed, common rue, burning bush). Prevention includes avoidance of exposure, using protective clothing like gloves, avoiding sunlight, and wearing sunscreen.