Bateman's purpura
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.
Bateman1 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.
Clinical aspects of dermatoporosis include morphological markers of fragility, such as senile purpura, stellate pseudoscars, and skin atrophy.2 The concept of the syndrome term dermatoporosis has been used to compare it to osteoporosis, implying both should be prevented and treated to avoid complications.
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.3 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.
History
Patients may report the appearance of purple blotches or bruises on their forearms, hands, face, or neck. The macules are not associated with pain or pruritus.
Constitutional symptoms (eg, fever, malaise, weight loss) are absent.
The patient may report a history of the lesions resolving and then subsequently reappearing. Residual brown pigmentation may appear after the purpuric macules resolve. Individual lesions usually last 1-3 weeks, and they do not undergo the color changes that occur with other types of purpuric lesions.
Patients are typically unaware of any external trauma that may have been responsible for the ecchymoses. Individuals may report a history of chronic sun exposure to skin sites where lesions are present. Individuals with actinic purpura are often taking blood-thinning medications such as aspirin or warfarin, which can aggravate the condition.
An asymptomatic petechial eruption after strong sun exposure may occur, sometimes with an action spectrum within the ultraviolet A waveband.5
Physical
Purpuric patches and macules larger than 3 mm in diameter are usually present on the extensor surfaces of the forearms and on the dorsa of the hands; the lesions do not extend onto the fingers. Ecchymoses may also be found on the neck and face. Macules and patches are dark purple and irregularly shaped. A sharp margin is seen between the borders of the lesions and the surrounding skin.
Some macules are more deeply colored than others because the duration of the lesions varies. The color changes that are typically associated with purpura or ecchymoses due to other causes do not occur, although residual brown pigmentation may persist.
Lesions of actinic purpura occur in areas of atrophic and inelastic photodamaged skin. Other signs of dermatoheliosis often present include leathered wrinkling, stellate pseudoscars, and a sallow yellow hue to the skin. Lentigines and scars may be present. The skin may appear darker secondary to hyperpigmentation due to hemosiderosis.
Causes
Chronic sun exposure leads to skin changes that predispose patients to actinic purpura. Because of the ultraviolet-induced atrophy, the connective tissue of the dermis is no longer able to adequately support the microvasculature. As a result, even minor trauma can tear the blood vessels, leading to the extravasation of blood.
Laboratory Studies
The diagnosis of actinic purpura is usually obvious at clinical examination. Laboratory investigation is not required unless the diagnosis is not readily apparent.
Findings of the following tests are in the reference ranges:
- Complete blood cell count
- Coagulation studies
- Platelet count determination
- Liver function studies
- Urinalysis
- Stool guaiac test
Histologic Findings
Biopsy reveals a thinned epidermis with many abnormal keratinocytes in a disorderly pattern. The upper dermis contains extravasated red blood cells and hemosiderin without evidence of inflammatory cells. At histologic evaluation, solar elastosis can be appreciated in the surrounding skin as faintly blue homogenized elastotic material lying just below a layer of normal connective tissue at the base of the epidermis. The amount of abnormal elastic fibers is markedly increased, and the amount of collagen is decreased.
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.
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.
