Disseminated superficial actinic porokeratosis

# Overview
Disseminated superficial actinic porokeratosis (DSAP) is a non-contagious skin condition with apparent genetic origin in the SART3 gene.:533 It most often presents in sun-exposed areas of the body.  Some DSAP cases have been reported in patients with acute immune compromised situations, particularly in the elderly.  For those with sun damaged skin, the lesions usually begin to appear in the patient's 20's and increase in number and visibility in the 40's or 50's.  Commonly, though not always, the number and visibility of lesions is in direct proportion to the amount of sun damage to the affected area.
Lesions generally are characterized by an irregularly-shaped thread-like ring that is usually the size of a pencil eraser, though lesions vary and may be half or double that size.  The thread-like ring is very thin, much like fabric thread for sewing, and raised such that it is both palpable and visible.  The interior of the ring may be rough like sandpaper, or smooth.  The interior is often discolored, though colors vary from patient to patient. Lesions, due to their vascular nature, can also vary according to body temperature, environmental temperatures, and other external stimuli.  The internal ring color is most often reddish, purplish, pink, or brown.
Some patients report itching and irritation associated with the condition, though many report no notable sensation at all.  Though no known hormonal link has been found, DSAP occurs more commonly in women.
A study in 2000 was done on a Chinese family, in which a locus for a gene was located.

# Diagnosis

## Physical Examination

### Skin
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. With permission from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Porokeratosis actinic. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.
- Segmental porokeratosis. Adapted from Dermatology Atlas.