Occurence of Light Sensitive Eczema

Light Sensitive Eczema is eczema caused by exposure to sunlight. Eczema that is caused by sunlight is rare. If it happens it is likely to occur on the face, hands and arms. Using high factor sun creams can treat it. Sometimes this eczema can be caused when people are taking medication that reacts to sunlight e.g. antihistamines and arthritis medications. Ingredients in soaps and cosmetics may also cause this.

Causes of Light Sensitive Eczema

The face is exposed to the environment and so is vulnerable to the effects of sunlight. Sunlight can make atopic eczema worse while in others it can help improve eczema. Seborrheic eczema may get worse initially then improve with sun exposure. Certain medications and chemicals can interact with sunlight to cause an allergic reaction called photo-allergy. When this happens, the areas of the face shielded from the light are usually spared (the eyelids, below the nose, under the chin and behind the ears). This differs from an airborne allergic contact dermatitis where all areas of the face are usually involved. Some (usually older) people develop a particularly severe form of unexplained sun sensitivity that causes extremely persistent eczema in light exposed areas of the face and elsewhere. This condition, which is termed 'chronic actinic dermatitis', is fortunately very unusual.

If light sensitive eczema is suspected, special skin tests with different wavelengths and doses of ultraviolet light are sometimes done, but these require special equipment and are only carried out in a few dermatology departments with expertise in the investigation of light sensitive skin disorders.

Photosensitivity occurs for a variety of reasons:

  • Medicines taken internally.
  • Contact with chemicals, fragrances or plant.
  • Autoimmune disease (self-allergy), particularly lupus erythematosus.
  • Porphyria, disorders in which there are increased porphyrins in the skin.
  • Polymorphic light eruption, actinic prurigo, solar urticaria and chronic photosensitivity dermatitis: all of unknown cause.
  • Genetic disorders, including xeroderma pigmentosum.

Although most people with the common skin conditions psoriasis and atopic eczema find sun exposure or ultraviolet light treatment helpful, about 10% report they cause flare-ups.

Photosensitizing medications can result in unexpected sunburn or a dry, bumpy or blistering rash on exposed skin (face, neck, arms, backs of hands and often lower legs and feet). The rash may or may not be itchy. They can also result in onycholysis (nail plate lifting off the nail bed). The most common medications causing photosensitivity are diuretics, tetracycline antibiotics and anti-inflammatory agents.

Skin contact with various chemicals may result in a toxic or allergic reaction on sun-exposed skin. Light sensitive eczema most often arises from tar products, fragrances and sometimes sunscreens.

Blisters and brown streaks may occur from touching certain plants followed by sun exposure. This is known as phytophotodermatitis. The most common causes are vegetables such as celery, parsley and their leaves as in the case with parsnips, carrots; fruit such as figs and citrus and umbelliferous weeds (e.g. hogweed) that contain photosensitizing psoralen chemicals.

Symptoms of Light Sensitive Eczema

Some people develop a rash because their skin is sensitive to sunlight; this is known as photosensitivity. Some forms of photosensitivity can also increase the risk of skin cancer.

Patients may not associate their skin complaint with the light. It is not always the bright summer sun, which is responsible; some people also react to winter daylight, and very sensitive subjects may even be affected by fluorescent lamps indoors.

Sunlight contains both ordinary visible light and shorter invisible light rays called ultraviolet radiation (UVR). UVR can produce tanning but also causes burning and skin cancer.

UVR is divided into UVB (short wavelength rays that cause sunburn and tan) and UVA (longer wavelength tanning rays). Patients can be sensitive to one kind of sunlight (i.e. only to UVB, UVA or visible light) or to a wider range of radiation. The most common photosensitivity is to UVA.

Controlling Light Sensitive Eczema

Effective treatment requires an accurate diagnosis of the particular type. More than one type of eczema can be present at the same time and in difficult cases the advice of a dermatologist may be needed. No tests are usually necessary unless allergic contact eczema is suspected.

In general, treatment of facial eczema involves:

  • Avoidance of the cause, if known e.g. avoidance of chemicals producing contact allergy, or the use of appropriate sunscreens to minimize sun exposure.
  • Regular application of bland moisturizers such as jojoba oil. These may take the form of greasy ointments (for very dry skin) or creams which are less greasy. Some people prefer using creams on the face during the day and ointments at night.
  • Avoidance of ordinary soap and use of soap substitutes such as emulsifying ointment. These may also be used by men as shaving soap substitutes.

For the most severely light sensitive patients, normal activities may be severely curtailed. Some find night work and sleep during the day, others put up with the rash.