Chronic Actinic Dermatitis (CAD) comprises a broad range of abnormal reactions
of the skin to ultra violet or other visible light radiation. The reactions
cause inflammation, sunburns and occur on sensitized skin, where the
sensitizers could be both external and internal agents.
It occurs mostly in people who are allergic to sensitizers, such as,
flowers, types of wood, perfumes, sunscreens and rubber compounds. More
than half the patients with chronic actinic dermatitis have a pre-existing
allergic contact dermatitis or an endogenous condition like atopic or
It affects mainly the exposed areas of the body. However, if UV light
is the cause, then even the unexposed areas can be affected, unless the
clothing totally blocks the light. The shaded areas affected, like, eyelids,
points to associated allergic contact dermatitis.
Chronic actinic dermatitis probably occurs worldwide, but in places,
it may remain undetected due to lack of diagnostic facilities. All skin
types are affected including black African – African Americans.
It is common among the elderly but youngsters between 12 to 14 years old
are being increasingly affected.
In some patients, chronic actinic dermatitis clears after a long time,
but it tends to remain unresolved in 80% patients, even 10 years after
diagnosis. The prognosis for the associated contact allergic dermatitis
is even worse, with some predicting chronic actinic dermatitis. However,
it is not a life threatening disease, but management of chronic actinic
dermatitis requires significant changes in life style to avoid certain
allergens and sunlight.
Symptoms include occurrence in areas exposed to sunlight or applied with
medications. The milder form looks like sunburn with the skin showing
redness, itchiness and scaly skin in patches. If chronic actinic dermatitis
occurs frequently, the skin may be thick and dark. In severe chronic actinic
dermatitis, vesicles and bullae may be seen. Bullae are bubble like formations
under the skin.
Risk factors include sunlight, diseases like porphyria and drugs like
birth control pills, phenothiazines, tetracycline sulfonamides, diuretics
The abnormal reactions consist of persistent light reactivity, actinic
reticuloid, photosensitive eczema and photosensitivity dermatitis.
The causes of chronic actinic dermatitis remain unknown. Whatever be
the cause cited, it must consider the broad range of chronic actinic dermatitis
reactions, the presence of allergic dermatitis in chronic actinic dermatitis
patients, its incidence in those with dermatitis, and its higher incidence
in elderly men.
Some of the causes given are:
Phototoxicity, where the direct effect of the UV rays or taking chemicals
or substances that make the skin more sensitive to UV light, can cause
Photoallergicity, where reactions occur when individuals exposed to sun
are also taking certain chemicals or medications that make their skin
allergic to sunlight.
Polymorphous light eruptions where the skin on exposure to sunlight,
develops a red rash, hives which are flat or raised red areas with irregular
borders, and vesicles which are small fluid filled bumps.
However, since all these causes are still hypotheses in need of confirmation,
for the present it is best to regard chronic actinic dermatitis as a condition
where an individual develops, for reasons unknown, increased allergic
susceptibility to some external and internal photo sensitizing agents.
Since chronic actinic dermatitis is caused by sunlight as well as artificial
UV light from tanning beds, it can be difficult to find the source of
the problem. One helpful way to proceed with the diagnosis is to check
the condition of the unexposed parts of the skin as, for example, the
skin under a watchstrap or bracelets.
Further diagnosis is done by photo testing, which consists of having
various areas of skin exposed to known amounts of light of specific wavelengths
and comparing the resulting reactions with that caused by the disease.
The procedure is painless and can be repeated to assess improvement.
Patch testing is another common way of confirming chronic actinic dermatitis
diagnosis. A range of chemicals is applied to the skin and left for two
days. The skin is then examined for reactions.
Skin biopsy may be required if there is an underlying medical problem.
Since external agents are involved in causing chronic actinic dermatitis,
an avoidance protocol is essential. This consists of avoiding direct exposure
to sunlight, as well as medications and topical creams that cause the
problems. Wearing hats, long sleeves and using sunscreen are good ways
to avoid UV radiation in sun light. A broad-spectrum zinc oxide sunscreen
is recommended. Protective plastic film on home and car windows may be
For sunburns, cold water, ice compresses and aloe vera lotions can have
soothing effects. In case of pain, aspirin may be taken. Corticosteroid
creams (Betamethasone 0.1%) can ease the pain, redness, and itching of
the inflammation. Topical steroids may be used in case of flares. High
potency steroids should be used for short periods. For severe cases, prednisone
pills can be a good medication.