Actinic Porokeratosis
I. Definition:
Actinic porokeratosis is an inherited skin condition causing dry patches mainly on the arms and legs. Actinic Porokeratosis is a special type of inherited “sun spot” and is sometimes confused with solar keratoses, but solar keratoses are more likely to arise on the face and hands. The tendency to Actinic Porokeratosis is inherited as an autosomal dominant characteristic, which means on average half of the children of an affected parent will also have the tendency. However a certain amount of accumulated sun exposure and perhaps other factors such as immune suppression are needed to bring this tendency out.
Actinic Porokeratosis appears on the sun-exposed skin of people of European descent. It tends to be more prominent in the summer and may appear less prominent in winter. New lesions have been provoked by ultraviolet light in sun lamps. The average age, which patients first notice Actinic Porokeratosis is about 35 to 40, and its frequency in affected families, increases steadily with age. It is rare in childhood.
The Actinic Porokeratosis lesion begins as a papule, brownish red or brown in color and usually around a hair follicle containing a scaly plug. It expands and a sharp, slightly raised, scaly ring. The skin within the ring is somewhat thinned and mildly reddened or slightly brown, but a pale ring may be seen within the ridge. The ridge itself is sometimes a dark brown. The central thickening usually disappears, but it may persist with an attached scale, follicular plug or central dell. Sweating is absent within the lesions. Sun exposure may cause them to itch. In sunny areas, lesions may be present in very large numbers and may change. In few cases the center of the area becomes very red and may be covered by thick scale.
II. Causes:
III. Treatment:
Unfortunately in our present state of knowledge there is no very satisfactory treatment for actinic porokeratosis. Over the years we have tried:
Nothing has proved very effective. Most people settle for just having the larger lesions frozen lightly and returning as necessary for further treatments, using a moisturizer to help reduce the dry feeling.
IV. Prevention:
Actinic porokeratosis is an inherited skin condition causing dry patches mainly on the arms and legs. Actinic Porokeratosis is a special type of inherited “sun spot” and is sometimes confused with solar keratoses, but solar keratoses are more likely to arise on the face and hands. The tendency to Actinic Porokeratosis is inherited as an autosomal dominant characteristic, which means on average half of the children of an affected parent will also have the tendency. However a certain amount of accumulated sun exposure and perhaps other factors such as immune suppression are needed to bring this tendency out.
Actinic Porokeratosis appears on the sun-exposed skin of people of European descent. It tends to be more prominent in the summer and may appear less prominent in winter. New lesions have been provoked by ultraviolet light in sun lamps. The average age, which patients first notice Actinic Porokeratosis is about 35 to 40, and its frequency in affected families, increases steadily with age. It is rare in childhood.
The Actinic Porokeratosis lesion begins as a papule, brownish red or brown in color and usually around a hair follicle containing a scaly plug. It expands and a sharp, slightly raised, scaly ring. The skin within the ring is somewhat thinned and mildly reddened or slightly brown, but a pale ring may be seen within the ridge. The ridge itself is sometimes a dark brown. The central thickening usually disappears, but it may persist with an attached scale, follicular plug or central dell. Sweating is absent within the lesions. Sun exposure may cause them to itch. In sunny areas, lesions may be present in very large numbers and may change. In few cases the center of the area becomes very red and may be covered by thick scale.
II. Causes:
- Repeated, prolonged sun exposure causes skin damage, which may develop into an Actinic Porokeratosis.
- The sun damage responsible for an Actinic Porokeratosis usually occurred years before the lesion forms.
III. Treatment:
Unfortunately in our present state of knowledge there is no very satisfactory treatment for actinic porokeratosis. Over the years we have tried:
- Cryotherapy
- 5-Fluorouarcil cream
- Alpha hydroxy acid cream
- Calcipotriol ointment
- Oral acitretin
- Photodynamic therapy
Nothing has proved very effective. Most people settle for just having the larger lesions frozen lightly and returning as necessary for further treatments, using a moisturizer to help reduce the dry feeling.
IV. Prevention:
- The above treatments do not prevent new Actinic Porokeratosis from forming. Daily sunscreen use (SPF 15 or higher) will help some, but most of the damage causing these growths occurred many years ago.
- Retin-A (Renova) and alpha hydroxyacid lotion applied daily to areas of sun-damaged skin will reverse some microscopic keratoses and help prevent new ones.