Prevalence of pruritus in the elderly in an outpatient dermatologic clinic: a monocentric pilot study

Abstract

Few studies have examined pruritus in elderly patients, a common dermatological condition. The study examines pruritus prevalence and characteristics in elderly patients referred to the Dermatology Unit, at Genoa’s Galliera Hospital. The demographic characteristics of all Outpatient Clinic patients with any skin condition were examined, focusing on pruritus patients over 65. Pruritus was present in 36/262 patients (14%; M:F =20:16; mean age: 59.55 years). About 14% of 140 patients aged ≥65 years had pruritus, with 20/262 (8%; M:F =14:6; mean age: 74.6 years) exhibiting it. Visual analog score pruritus did not differ between patients aged ≥65 years (20/36) and <65 years (16/36) statistically. In 89% of patients, itch was related to a dermatological condition, mainly psoriasis. Only extracutaneous diseases resulted more frequently in the patients aged >65. No anamnestic link was found between drug use and pruritus in these patients. We confirm that pruritus is a common skin problem that affects both sexes, young and old, and is almost always caused by an underlying skin condition (mainly psoriasis). It is rarely caused by a new drug.

Introduction

Pruritus may be considered acute (lasting less than 6 weeks) or chronic (lasting more than 6 weeks) and both acute and chronic manifestation of itching that is frequently observed among patients who require a dermatological evaluation.¹ Pruritus may be localized or generalized and it is frequently associated with many inflammatory skin or systemic diseases.² Especially when it is not accompanied by any skin lesions, it represents a major diagnostic and therapeutic challenge.

Pruritus in the elderly can be defined as chronic itching in a patient over 65 years old.³ The underlying causes of itch in the elderly are multifactorial and they seem linked to skin aging, immunosenescence, neurological/psychological changes with aging or drugs,⁴ therefore a detailed medical history including drug intake is required. Chronic pruritus in the elderly may cause severe discomfort and pain.⁵ Only a few studies have investigated pruritus in old patients.⁶

Materials and Methods

We performed a monocentric prospective observational study to investigate the prevalence of pruritus in patients which refer to the Dermatology Unit, Galliera Hospital in Genoa, particularly focusing on patients aged more than 65 years and without taking into consideration common confounding factor as xerosis cutis and drugs intake (if not directly related to pruritus).

We evaluated the demographic characteristics of all the patients attending for any skin condition in the Outpatient Clinic at the Dermatology Unit at Galliera Hospital, Genoa (Italy) from February 1^st, 2020, to February 28^th, 2020. Because of the Coronavirus disease 2019 (COVID-19) emergency, on March 9^th, 2020, Italy went into lockdown imposing the closure of nonurgent outpatient clinics therefore it was not possible to extend longer the study. This study was approved by the regional Ethics committee (#154REG2019 - DB id 4544; 20.3.2019). Inclusion criteria were: age >18 and sign of the consent form. All the patients who signed the consent form and who complained also pruritus were then asked to complete a visual analog scale (VAS) assessment for both pruritus and pain (Figure 1).⁷ Based on the literature, VA S categories were considered as follows: 0 = no pruritus, >0-<4 points = mild pruritus, ≥4-<7 points = moderate pruritus, ≥7-<9 points = severe pruritus, and ≥9 points = very severe pruritus.⁷ Moreover, both qualitative and quantitative characteristics were assessed for each patient: age, sex, Fitzpatrick skin type, drug intake (recorded only if an anamnestic relevant association with pruritus was reported; usual medications were not recorded), relevant previous medical history, presence or absence of a concomitant dermatological condition; clinical features and distribution of skin lesions. Similarly to drug intake and in order to avoid a confounding factor, also xerosis cutis was not recorded because it is extremely frequent in the elderly (about 50% of patients).⁸

Categorical variables were reported as frequency and percentage. Continuous variables were reported as mean and standard deviation (SD) and compared with the t-test. An alpha level was set to 0.05.

Results

A total of 262 patients (139 males, 123 females; mean age ± SD: 59.91±20.8) were enrolled in this study (Figure 1). The total number of patients aged ≥65 years was 140 patients (53.4%). Pruritus was present in 36 out of 262 patients (14%; M 20; F 16; mean age 59.55). Fitzpatrick skin type most commonly observed in patients with pruritus was type II (19 patients, 52.8%) followed by type III (5 patients, 13.9%), type V (3 patients, 8.3%), type IV (2 patients, 5.6%) and in 7 patients (19.4%) this data was not available.

Patients with pruritus older than 65 years were 20 out of 262 (8%; M 14; F 6; mean age 74.6), that represented 14% out of the 140 patients aged ≥65 years. All together for the 36 patients with itching, VAS pruritus ranged from 5 to 10 and VAS pain ranged from 0 to 4. Considering separately the patients aged ≥65 years (20 out of 36 patients with pruritus, 55.6%), the VA S score was assessed in 19 patients and the mean value was 6.60±1.42 (range 4-9); in younger patients, aged <65 years (16 out of 36 patients with pruritus, 44.4%), VA S score was assessed in 15 patients and the mean value 7.09±1.25 (range 5-10). This difference was not significant (P=0.41).

The severity of pain assessed by the VAS was higher in older subjects with a mean value of 1.6±1.71 (range 0-4), while in younger patients the mean value was 1.33±1.35 (range 0-3). This difference was not significant (P=0.68).

Regarding duration, 17 patients (47%) defined pruritus as chronic, 6 patients as continuous (17%), and 27 patients as discontinuous (75%). Regarding general features, pruritus was reported as diffuse by 10 patients (28%) and circumscribed by 24 patients (67%). In 32 patients (89%) pruritus was related to a dermatological condition while in only 4 patients (11%) it was present in unaffected skin (pruritus sine materia).

Table 1 illustrates the diagnosed dermatological conditions associated with all patients with pruritus while Table 2 refers only to patients older than 65 years. In general, pruritus was commonly associated with nummular eczema, urticaria, and psoriasis, which resulted frequent in both groups (younger and older than 65 years). However, there was no statistical difference between the two groups in terms of diagnoses of eczema, psoriasis, and atopic dermatitis. On the contrary, extra-cutaneous diseases resulted more frequent in patients aged >65, particularly blood hypertension (Table 3). 75% of the patients with pruritus aged ≥65 years were in multidrug treatment, i.e., for blood hypertension, diabetes mellitus, hypotiroidism, hepatitis C virus infection, or chemotherapic agents. However, in none of these patients, an anamnestic association between drug intake and the onset of pruritus was observed.

Figure 1.

Study outline and demographics.

Table 1.

Dermatological conditions associated with pruritus in 32 patients (both <65 years old and ≥65 years old) with skin lesions.

Dermatological condition	Total	%
Nummular eczema	6	16
Prurigo simplex	5	14
Psoriasis	5	14
Urticaria	4	11
Pruritus sine materia	4	11
Lichen simplex chr.	3	8
Seborrheic dermatitis	2	5.5
Tinea corporis	2	5.5
Insect bite	1	3
Scabies	1	3
Prurigo nodularis	1	3
Intertrigo	1	3
Atopic dermatitis	1	3

Table 2.

Dermatological conditions associated with pruritus in 20 patients ≥65 years old.

Dermatological condition	Total	%
Psoriasis	5	25
Prurigo simplex	5	25
Urticaria	1	5
Lichen simplex chr.	1	5
Seborrheic dermatitis	1	5
Scabies	1	5
Prurigo nodularis	1	5
Nummular eczema	1	5
Pruritus sine materia	4	20

Table 3.

Systemic diseases recorded in patients with pruritus.

	<65 years	>65 years
Heart insufficiency	0	0
Blood hypertension	1	5
Crohn’s disease	0	1
Hypotiroidism	1	2
Benign prostatic hypertrophy	0	2
Gastroesophageal reflux disease	0	1
Diabetes mellitus	0	1
Breast cancer	0	1
Hepatitis C virus infection	0	1

Discussion

Our study was a monocentric pilot one-month-long investigation about frequency and type of pruritus in elderly patients attending our Outpatient Clinic for any skin condition, without considering xerosis cutis or usually drug intake in order to avoid selection bias.

In fact, xerosis cutis is highly frequent in the elderly (more than 50% of those aged 65 years or older) as a consequence of loss of barrier function of the skin and, therefore, itching caused by xerosis may be merely incidental.^5,9 Also, many systemic common drugs usually regularly assumed by old patients may induce pruritus, such as antihypertensive drugs, antiarrhythmics, anticoagulants, antidiabetic drugs, hypolipemic drugs, antibiotics, chemotherapeutics, psychotropics, neuroleptics, antiepileptics, cytostatics, cytokines, growth factors, monoclonal antibodies and others such as nonsteroidal anti-inflammatory drugs, but almost any drug may induce pruritus by various pathomechanisms.^6,10,11 Although drug-induced pruritus (in the case of pruritus without skin rash) is not a distinct category but summarized under “systemic origin” according to the International Forum for the Study of Itch (IFSI) classification, this adverse effect should be taken into account when assessing patients with chronic itch.^10,11 In our study, we recorded drugs only if a relevant anamnestic association with pruritus was reported. In our 36 patients with pruritus, an anamnestic direct association of drug-induced pruritus was not observed.

We confirm that pruritus is a common dermatological symptom, being present in 14% of both the general population and patients older than 65 years, without statistically significant differences in VAS pruritus and pain between patients younger or older than 65 years. Only a few authors investigated pruritus in the elderly and these studies were characterized by selection bias and differing endpoints (pruritic skin disease or itch).^12,14 In 2006, a study assessing retrospectively more than 4000 patients aged 65 years or older, found that pruritus was responsible for 11.5% of admissions, being the third most common cause of hospitalization and in line with our observation.¹² Contrarily, Beauregard et al., in 1987, found that pruritus in the elderly represented 29% of all complaints; Beauregard et al.¹³ and Thaipisuttikul,¹⁴ in 1998, reported even higher frequency (41%).¹⁴ Interestingly, in our experience, we did not find a higher frequency of pruritus in older than in younger patients, in contrast with other studies that reported pruritus more common in the elderly.³

In almost all patients (89%) itching was an accompanying symptom related to an underlying dermatological condition. Pruritus was reported as chronic in almost half of the patients, and described as diffuse in one-third of them. Nummular eczema was the most frequent skin disease recorded in patients younger than 65 years, while other common itching skin diseases like atopic dermatitis, urticaria, and scabies were registered with low frequency in both groups. Prurigo nodularis was observed in only two patients. Interestingly, pruritus was commonly associated with psoriasis in both groups, younger than 65 years (16%) and older than 65 (25%). In the literature, it is reported that pruritus affects a higher percentage of patients with psoriasis, about 60-90%, a frequency even higher than our observation.^15,16

The IFSI classification distinguishes three groups of pruritic individuals:^10,11 those having pruritus on diseased skin (group I), pruritus on non-diseased skin (group II), and pruritus with secondary skin scratch lesions (group III). In our study, 11 patients were classified as group I (having pruritus on diseased skin), 4 subjects in group II, and 5 in group III, according to IFSI classification. Patients of group II refer to the old definition of “senile pruritus”, renamed also idiopathic itch of the elderly or Willan’s itch and it should be reserved for only generalized pruritus in the absence of xerosis cutis or other recognizable cause.⁹

Chronic diseases are very common in the elderly population and pruritus may also characterize different underlying systemic diseases, i.e., among others renal insufficiency, hematological, hepatic, or neurological disorders.³ We did not find a statistically significant difference concerning the recorded systemic disease among the 2 groups. We did not observe renal, hematologic, and neurological-related pruritus probably because of the relatively short period of observation and the population enrolled that referred only to outpatient than to an inpatient.

Limitations of our study regarded mainly the monocentric outline, the short period of observation (due to the COVID-19 lock-down), the small population, and the enrolled patients that were referred only to an outpatient clinic which differs from an inpatient population.

Conclusions

In conclusion, we report the picture of the frequency of pruritus in patients attending an Italian outpatient dermatologic clinic, without taking into consideration common confounding factors such as xerosis cutis and drug intake (if not directly related to pruritus). We confirm that pruritus is a common skin problem, that is equally frequent in young and old patients, that in almost all cases is related to an underlying skin condition (mainly psoriasis) and that is rarely anamnestic related to a new drug intake. Further multicentric larger studies are needed to confirm and expand our observations.

Funding Statement

Funding: none.