Skin picking disorder (SPD), also known as excoriation disorder or dermatillomania, affects up to 5.4% of general population and up to 30% of psychiatric patients.1 It was included as a formal diagnosis in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM 5), characterized by the following: recurrent picking at the skin resulting in skin lesions; attempts to stop picking; clinically significant distress, and absence of another cause for the habit.2 SPD severity is related to impairment in quality of life, and is correlated with anxiety disorder (up to 48%), major depression (8–28%), and substance abuse (14–36%).3

Although it is a psychiatric disorder, the majority of patients first seek help with a dermatologist, and differential diagnosis should be made with delusional parasitosis, prurigo simplex, subacute Hebra and scabies.4 Among patients with SPD who seek help, only 53% receive the correct diagnosis, made by dermatologists in 2.5% of cases and by psychiatrists in 56%.1 SPD is a chronic disorder and the habit usually is automatic, with only 24% of individuals reporting full awareness prior to picking.5 Besides the nails, patients can use pins or tweezers to manipulate their skin, and 80% have notable tissue damage.1

The severity of SPD and the response to treatment have been evaluated with different instruments: clinician-reported measures, self-reported measures of SPD severity, and self-reported measures of SPD impact. The Yale-Brown Obsessive Compulsive Scale Modified for Neurotic Excoriation (NE-YBOCS) is a reliable clinician-reported instrument that evaluates thoughts and behaviors related to skin picking during the last seven days, but does not specifically assess the social distress caused by the disease.6 Among the self-reported measures, the skin picking scale is a moderately reliable instrument that assesses SPD severity during the past week and that has been correlated with depressive symptoms.7,8 The Skin Picking Symptom Assessment Scale is a less-used, reliable, self-reported instrument to evaluate SPD severity during the last seven days.6 The Skin Picking Reward Scale is a reliable instrument to assess the aspects of “liking” and “wanting” the SPD habit, without definition of the time of symptoms evaluation, substantially influenced by the self-reflection regarding the habit.6 All these measures evaluate the frequency of this habit but not the distress caused. The Skin Picking Impact Scale (SPIS) is the only scale that evaluates the psychological impact of this disorder; it is a patient-rated scale with high reliability, evaluating symptoms during the last seven days, with higher scores considered more severe impact. The SPIS has been correlated with depressive and anxious symptoms.9

The available instruments to assess SPD depend of the patient's awareness about the habit, which is not common. The NE-YBOCS also depends on clinician knowledge about emotional distress, which is not easy for dermatologists, who are generally the first professional accessed by patients suffering from SPD. Self-applied instruments are also influenced by emotional aspects of the patient: anxiety, depression, and social avoidance, which is frequent in SPD. In addition, the body area affected directly influence the scales, with patients who pick their faces generally having a high score because of higher self-esteem impact.10 The majority of instruments evaluate the habit during last seven days, although it is known that SPD is a chronic disease and that the time to heal severe wounds would be longer. Even though there are different methods of evaluation for SPD, no study has evaluated skin-picking severity through different approaches at the same time.

There is a lack of an objective way to assess SPD symptoms not influenced by patients’ awareness of the habit or other emotional conditions. A potential advantage of a photographic evaluation is the reduction of reporting bias and recognition of the severity of the skin lesions. To the authors’ knowledge, no photographic measure has been validated to assess SPD severity, with only two studies having used photographs to evaluate SPD, without validity or reliability of the measure being published.11,12

Despite the high prevalence of SPD, to the authors’ knowledge no instruments to assess this pathology have been validated to be used in the Brazilian population. As the impact of SPD on a patient's life is important information about the individual's suffering, and because the SPIS, a highly reliable scale, was previously translated to Brazilian Portuguese (Ferrão Y.A. and Bedin, N.R., data not published), the validation of this instrument for Brazilian population could be a valuable way to assess SPD.

The aim of this study is to validate the SPIS for the Brazilian population and to create a photographic instrument (PI) to assess SPD severity, applicable by dermatologists. This study works with the hypothesis that the SPIS and the PI can be reliable and easily used in clinical practice, with PI reflecting more directly the severity of SPD, independently of comorbid symptoms. In this way, the diagnostic rates of SPD can be increased.

The study included 63 patients. Table 1 depicts the epidemiological and sociodemographic characteristics of the sample.

The validation of the SPIS resulted in a Cronbach's alpha of 0.88. The exploratory factor analysis showed a two-factor scale, resulting in a RMSEA<0.00001, with chi-squared goodness-of-fit test=21.61; p<0.71, and TLI=1.034. Fig. 1 shows the translated SPIS.

Figure 1.

Skin Picking Impact Scale validated for Brazilian Portuguese.

(0.39MB).

The PI created by the two experts is shown in Fig. 2. Cronbach's alpha was 0.87 and the reliability was moderate, with intra-class correlation of 0.6. Table 2 shows the detailed information about the PI scores and reliability values. The exploratory factor analysis found a one-factor model, with the sub-item ‘Active Excoriation’ having the largest factorial load, of 0.978.

Figure 2.

Photographic instrument to assess skin lesions caused by skin picking disorder.

(0.14MB).

Analyzing the correlation between the instruments, the SPIS was correlated with the anxious and depressive symptoms evaluated by the HAM-A and BDI scales. However, the PI was not correlated with the CGI, nor with comorbid symptoms (Table 3).

Evaluating patients according to the region of lesions, those with lesions in the face tend to have a higher CGI score than patients without, but this did not reach statistical significance (mean=4.95, SD=1.22 vs. mean=4.32, SD=1.29; p=0.08).

This study validated the SPIS to be used in the Brazilian Portuguese version as a reliable instrument. The SPIS is a self-applied instrument that does not depend on clinician knowledge about SPD. Although SPD is a prevalent condition, many clinicians are not familiarized with this diagnosis and in many cases non-psychiatric professionals are the first sought by patients, leading to underestimation in the diagnosis and impact on life of SPD. Having a self-applied scale able to be used by all health professionals is a reasonable way to increase the assessment of SPD diagnosis and severity, overcoming the barrier of low referral to treatment.1,4

In order to assess skin-picking lesions in an objective way, two dermatologists created the PI, measuring SPD based on severity of the active lesions in the skin. To date, despite having many scales to assess SPD, there is no instrument to directly evaluate the lesions caused by the habit. It is known that patients can cause severe lesions, sometimes using objects to manipulate the skin, leading to infections and in more extreme cases septicemia and death.25 The lesion severity is not always associated with the impact on life of SPD, as patients with small lesions in the face can have higher scores on the SPIS than patients with extensive covered lesions.10 The PI created in this study can be an appropriate instrument to assess lesions from SPD, improving the diagnosis of severe lesions not assessed by existing scales and facilitating earlier treatment. This instrument was easily applied by different evaluators.

As expected, the Brazilian Portuguese version of the SPIS had a positive correlation with the patients’ global clinical status and their depressive and anxious symptoms. The high rates of patients with depressive and/or anxious syndromes in this study reflect the high rates of comorbidity of SPD and depression/anxiety. The PI created had no correlation with comorbid symptoms, the global clinical status, nor the SPIS, suggesting that the severity of lesion is not associated with individual life impact. Indeed, dermatologists of this study tended to underestimate the severity of SPD impact when evaluating only skin lesions. Although not statistically significant, this study found a more severe global clinical condition in those patients with more exposed lesions, independent of the lesion severity, which is in accordance with literature.10

The present results should be interpreted in light of some limitations. The sample was collected through advertising, which may have generated a selection bias, as patients with low SPD life impact, despite having severe lesions, might not have felt motivated to access this service. On the other hand, patients with extremely severe SPD life impact, with associated social impairment, may not have felt in condition to spontaneously look for health assistance. The strengths of this study are the sample size, powerful in comparison with previous studies, the well-established statistical methods used, and the innovative findings.22,26,27

The Brazilian Portuguese version of the SPIS is a valid and reliable instrument to assess SPD severity and its impact on life in Brazilian individuals, which is easily applied by psychiatrists and non-psychiatric clinicians. A PI to evaluate the severity of lesions caused by SPD can be applied by dermatologists and objectively reflects the lesion severity, although not reflecting the suffering of the individual. To improve SPD diagnosis, both instruments should be applied in the evaluation of the patient. Further studies are expected to assess the validity of the Brazilian Portuguese version of the SPIS when used to assess response to treatment. Also, future studies should evaluate if the PI can be applied by non-dermatologists, and if it can be a reliable way to assess the patient's improvement after treatment.

A grant was provided to the first author by The Ministry of Education (MEC) – Fundação Coordenação Aperfeiçoamento de Pessoal de Nível Superior (CAPES).

Alice Castro Menezes Xavier: Statistical analysis; approval of the final version of the manuscript; conception and planning of the study; elaboration and writing of the manuscript; obtaining, analyzing and interpreting the data; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the literature; critical review of the manuscript

Camila Maria Barbieri de Souza: Approval of the final version of the manuscript; conception and planning of the study; obtaining, analyzing and interpreting the data; critical review of the manuscript.

Luís Henrique Fernandes Flores: Approval of the final version of the manuscript; conception and planning of the study; obtaining, analyzing and interpreting the data; critical review of the manuscript.

Clarissa Prati: Conception and planning of the study; obtaining, analyzing and interpreting the data; critical review of the manuscript.

Cecilia Cassal: Conception and planning of the study; obtaining, analyzing and interpreting the data; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied.

Carolina Blaya Dreher: Statistical analysis; approval of the final version of the manuscript; conception and planning of the study; elaboration and writing of the manuscript; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the manuscript.

The authors declare no conflicts of interest.