The third type of contact dermatitis is caused by an interaction between products applied unto the skin to which a person has been previously sensitized, and the UV rays of the sun.

Mechanism of the reaction

You read it right. Chemicals on your skin could also cause eczema on the exposed area. There are two subtypes of the reaction: photoallergic and phototoxic.

A photoallergic reaction occurs when the allergen from certain physical agents on the skin are activated by sunlight and triggers an immune response. The reaction may vary per individual. More often, it manifests as red, itchy spots with small blisters that may erupt within minutes to hours, but usually after 24 hours after sun exposure. On the other hand, phototoxic reactions resemble sunburn due to direct tissue damage by light-activated photosensitizing substances. Products involved in photocontact dermatitis include one or more of the following:

• perfumes
• aftershaves
• sunscreens
• coal tar derivatives
• drugs (e.g. topical corticosteroids, tetracycline, chlorpromazine, promethazine, furosemide)
• citrus plants (lime juice)
• plants from Umbelliferae family (parsley, celery, parsnip)

What your Doctor can do for you

A detailed history of photosensitivity and exposure to potential photosensitizers along with the clinical manifestations supports the diagnosis of photocontact dermatitis. Treatment focuses more on relieving symptoms rather than curing the hypersensitivity disorder. Oral beta carotene is beneficial for some people to reduce photosensitivity. Corticosteroids will help with the inflammation and prevent further symptoms. The patient is advised to use emollients to prevent drying of the skin. Itching may be managed by the application of calamine over the site. But despite these measures, the best management for any form of dermatitis, photosensitivity, or allergic reaction is to keep away from the offender.

What you can do

While several treatment methods are available for the treatment of nay form of dermatitis, but the most important point in preventing the occurrence of any skin reaction is the avoidance of any factor that can aggravate the condition. Support healing of the affected tissue by using moisturizers and mild soap to prevent irritation. After shower, pat the skin dry instead of rubbing it with the towel. Avoid scratching the site as dirty fingernails may introduce bacteria and cause a secondary infection. And lastly, consult your physician for alternative products fit your skin type.