Senile Purpura: Clinical Features and Related Factors.

Dear Editor:

Senile or actinic purpura commonly presents as purpuric macules and patches on the sun-exposed skin in elderly individuals. The prevalence of senile purpura is approximately 10% in elderly individuals1. Senile purpura is considered a consequence of skin aging primarily attributable to photodamage and is often called dermatoporosis2. Although it is a common and clinically important condition, only a few studies have described in detail the clinical features or factors related to senile purpura3.

We performed a cross-sectional study using questionnaires to assess the clinical features and other factors related to senile purpura at Seoul National University Hospital (SNUH) and 20 local senior welfare centers between October and December 2017. The study protocol was approved by the Institutional Review Board of SNUH (IRB no. 1708-137-879), and written informed consent was obtained from all participants.

Patients enrolled in the study were asked whether they have/had senile purpura. Using a digital thickness micrometer (Mitutoyo Corporation, Kanagawa, Japan), double fold of skin thickness was measured at the level of the extensor area of the right lower arm 15 cm away from the elbow.

We used 2 questionnaires in this study—the first to assess the epidemiology and the second to assess other factors related to senile purpura. The epidemiological questionnaire included information regarding present lesions or a history of senile purpura, age of onset, frequency of development of lesions, persistence, sites of lesions, seasonal variations, inciting factors, inconvenience, and intent-to-treat analysis.

The questionnaire regarding other factors related to senile purpura included the patient's medical history, lifestyle factors, and sun exposure-related factors, skin care habit and occupational history. Diagnosis of current lesions was confirmed based on the history and the current medications administered. The questionnaire assessing sun exposure- related factors was a modified version obtained from Zhu et al.4

The IBM SPSS software version 23.0 (IBM Corp., Armonk, NY, USA) was used for statistical analysis. The Pearson's chi-square test, the Fisher exact test, or the linear association method was used to compare categorical data. The Student's t-test or the Mann–Whitney U test was used for intergroup comparisons of continuous variables. Binary logistic regression was performed to assess the other factors related to senile purpura. Patient-related factors that showed p<0.10 using univariate logistic regression analysis were subjected to multivariate logistic regression analysis. A p-value <0.05 was considered statistically significant.

Among the patients investigated, 57 (29.5%) reported senile purpura at the time of this study (n=27, 14.0%) or a history of senile purpura (n=30, 15.5%). The mean age of onset was 71.0±10.0 years. The most common site of purpuric lesions was the lower arms and hands (n=55, 96.5%), followed by the lower legs and feet (n=30, 52.6%), and the thighs (n=20, 35.1%). Approximately one-third of the patients investigated (n=17, 29.8%) reported that they almost always had senile purpura lesions. More than 50% of patients (n=34, 59.6%) reported that the purpuric lesions persisted for <2 weeks, whereas 11 (19.3%) patients reported that their lesions lasted >3 weeks. Most patients (n=40, 70.2%) reported no seasonal clinical fluctuations. More than 50% of patients (54.4%) reported that minor trauma was an inciting factor. Notably, 22 (38.6%) patients did not report any inconvenience from senile purpura, whereas 13 (22.8%) reported interference in their daily lives (Supplementary Table 1).

No statistically significant differences were observed in demographic characteristics between patients with senile purpura and controls (Table 1). Skin thickness in the senile purpura group was lesser than that in the control group. (p=0.010) Cardiac disease, dyslipidemia, and anticoagulation treatment rates in the senile purpura group were significantly higher than those in the control group (p=0.003, 0.018, and <0.001 in each).

Table 1

Demographics and medical history of the subjects

Characteristic	Senile purpura (n=57)	Control (n=136)	p-value
Sex (male/female)	27/30	46/88*	0.090
Age (yr)	78.2±6.6	77.5±6.2	0.524
Height (cm)	160.2±9.5	158.3±7.5	0.216
Weight (kg)	59.0±9.1	8.5±10.2	0.757
Body mass index (kg/m2)	23.4±3.1	23.43±3.2	0.873
Skin double-fold thickness (mm)			0.010
<4	18 (31.6)	28 (20.6)
4~6	23 (40.4)	62 (45.6)
>6	9 (15.8)	46 (33.8)
Previous history of stroke	3 (5.3)	6 (4.4)	0.725
Cardiac disease	15 (26.3)	13 (9.6)	0.003
Hypertension	37 (64.9)	71 (52.2)	0.105
Diabetes mellitus	15 (26.3)	29 (21.3)	0.451
Dyslipidemia	24 (42.1)	34 (25.0)	0.018
Anticoagulation treatment	23 (44.2)†	22 (17.3)‡	<0.001
Any dermatologic disease history	34 (59.6)	38 (27.9)	<0.001
Other diseases history	22 (38.6)	40 (29.4)	0.213

Values are presented as number only, mean±standard deviation, or number (%). *Two missing values exist. †Five missing values exist. ‡Nine missing values exist.

In terms of lifestyle, patients with senile purpura showed a higher smoking tendency (p=0.010) and a lower disposition for exercise, although the difference was statistically non-significant (mild exercise, p=0.065; Supplementary Table 2). Other lifestyle factors did not appear to be statistically significant. No significant intergroup difference was observed in both lifetime sun exposure and other sun exposure-related factors (Supplementary Table 3).

Univariate logistic regression analysis showed 7 statistically significant factors (Table 2). Multivariate analysis showed that dyslipidemia (p=0.003), anticoagulant treatment (p=0.027), a history of dermatological disease (p=0.004), and mild exercise (none vs. 5~7 days per week, p=0.017) demonstrated statistically significant intergroup differences.

Table 2

Logistic regression analysis for the related factors of senile purpura

Characteristic	Purpura/without purpura (number)	Unadjusted OR (95% CI)	p-value	Adjusted OR (95% CI)*	p-value
Sex
Male	27/46	Reference		Reference
Female	30/88	0.581 (0.309~1.091)	0.091	1.313 (0.309~5.578)	0.712
Cardiac disease
No	42/123	Reference		Reference
Yes	15/13	3.379 (1.487~7.681)	<0.001	1.930 (0.585~6.366)	0.280
Dyslipidemia
No	33/102	Reference		Reference
Yes	24/34	2.182 (1.135~4.194)	0.019	4.088 (1.598~10.458)	0.003
Anticoagulant treatment
No	29/105	Reference		Reference
Yes	23/22	3.785 (1.852~7.735)	<0.001	3.052 (1.138~8.186)	0.027
Any dermatologic disease history
No	23/98	Reference		Reference
Yes	34/38	3.812 (1.994~7.290)	<0.001	3.586 (1.490~8.633)	0.004
Skin double fold thickness (mm)
>6	9/46	Reference		Reference
4~6	23/62	1.896 (0.802~4.480)	0.145	2.115 (0.719~6.223)	0.174
<4	18/28	3.286 (1.299~8.310)	0.012	2.436 (0.735~8.077)	0.146
Smoking (pack year)
Non-smoker	30/98	Reference		Reference
Less than 20	9/14	2.100 (0.827~5.333)	0.119	2.555 (0.539~12.119)	0.237
More than 20	17/22	2.524 (1.188~5.363)	0.016	4.025 (0.718~22.554)	0.113
Mild exercise activity
None	15/23	Reference		Reference
1~4 days per week	13/25	0.797 (0.313~2.029)	0.635	0.424 (0.122~1.478)	0.178
5~7 days per week	29/88	0.505 (0.233~1.096)	0.084	0.262 (0.088~0.783)	0.017

OR: odd ratio, CI: confidence interval. *Adjusted for age, sex and all variables above mentioned.

Senile purpura is considered a self-healing cutaneous disease without sequelae. Recently, skin tears are commonly being reported and are bothersome issues in elderly patients5. Most clinical aspects of senile purpura observed in this study concurred with previous studies. Lesions were most commonly observed on the extremities, and usually disappeared within 3 weeks. Most patients did not view this condition as more than a cosmetic issue at best; however, >20% of patients reported that senile purpura lesions interfered with their daily life.

Senile purpura is often called actinic purpura owing to its association with chronic sun exposure6. Interestingly, we did not observe any distinct correlation between senile purpura and a history of sun exposure. Notably, in this study, medical and lifestyle factors were significantly associated with senile purpura. Anticoagulant therapy frequently induces purpura and is also an independent risk factor for dermatoporosis7. Evidence regarding the association between dyslipidemia and senile purpura is limited. It can be assumed that dyslipidemia might cause dysfunction or inflammation of cutaneous vessels89. The association between senile purpura and a history of dermatological disease might be explained by exposure to topical or systemic corticosteroids, which is a known risk factor for dermatoporosis210. Multivariate analysis showed that lack of exercise is a significant factor related to senile purpura. Previous studies have reported that exercise is associated with increased skin thickness10.

Limitations of our study: 1) The cross-sectional design of this study did not allow assessment of the cause-and-effect relationship; 2) This was a questionnaire-based study; thus, medical history was not obtained from the medical record system and recall bias could have potentially interfered in the questionnaires.

In conclusion, this study suggests that current medication status including dyslipidemia or anticoagulants, a history of dermatological disease, and lack of exercise could potentially serve as factors related to the development of senile purpura. Further studies are required to elucidate the pathophysiology of senile purpura.