Actinic Purpura

Background

Actinic purpura is a benign clinical entity resulting from sun-induced damage to the connective tissue of the dermis. Actinic purpura is characterized by ecchymoses on the extensor surfaces of the forearms and the dorsa of the hands that usually last 1-3 weeks.

Bateman first described the condition in 1818 when he noted dark purple blotches and determined that they were due to the extravasation of blood into the dermal tissue. Hence, it is sometimes called Bateman purpura.

It is common in elderly individuals and usually occurs after unrecognized minor trauma to the respective areas.

Pathophysiology

The purple macules and patches of this condition occur because red blood cells leak into the dermal tissue. This extravasation is secondary to the fragility of the blood vessel walls caused by ultraviolet radiation–induced dermal tissue atrophy. This atrophy renders the skin and microvasculature more susceptible to the effects of minor trauma and shearing forces. The insult to the skin is typically so minor that isolating it as a cause of the ecchymoses can be difficult.

Notably, no inflammatory component is found in the dermal tissue. The absence of a phagocytic response to the extravascular blood has been postulated to be responsible for delaying resorption for as long as 3 weeks.

Actinic purpura may be, along with osteoporosis, a sign of collagen loss in skin and bone.² This causal loss of skin collagen has been confirmed when collagen was expressed absolutely, instead of as a percentage or ratio. That is, women have less collagen than men and it decreases by 1% a year in exposed and unexposed skin. These changes in skin collagen may correspond to changes in bone density. The hypothesis is that the changes in skin collagen also occur in bone collagen, leading to the associated changes in bone density.

Frequency

United States

Actinic purpura is an extremely common finding in elderly individuals, occurring in approximately 11.9% of those older than 50 years. Its prevalence markedly increases with years of exposure to the sun.

International

Data are not available.

Mortality/Morbidity

The ecchymoses may be cosmetically distressing and may leave dyspigmentation or scarring, but the lesions are not associated with any serious complications.

Race

The effects of chronic sun exposure with the resultant ultraviolet radiation–induced skin changes occur more often and are more pronounced in fair-skinned individuals than in others.

Sex

Both sexes are equally affected.

Age

• Actinic purpura occurs almost exclusively in the elderly population, though it may sporadically occur in younger people.
• The incidence varies with respect to age.
• Approximately 2% of those aged 60-70 years and as many as 25% of those aged 90-100 years can have the purpuric lesions.

Treatment

Medical Care

• Actinic purpura does not require extensive medical care.
• • To prevent further ultraviolet-induced damage to the skin, sunscreens that provide both UV-A and UV-B protection should be applied daily, especially to areas affected by the purpuric lesions.
  • Patients should also use barrier protection (eg, clothing).
  • Inform patients that sunscreens help prevent but do not reverse the photodamage.

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• Tretinoin has been observed to reverse many changes that occur with photodamage.
• • The use of tretinoin may be beneficial in actinic purpura because photodamage is ultimately responsible for this disorder.

  • Tretinoin increases the amount of dermal collagen and decreases the amount of abnormal elastin when applied topically. However, to the authors' knowledge, no results demonstrate that actinic purpura lesions improve with the topical application of tretinoin.

Activity

• Advise patients with actinic purpura to limit their sun exposure by applying sunscreen daily or by avoiding sun exposure altogether.
• Instruct patients to minimize any trauma to the skin where the purpuric lesions are present.