Some dermatologic disorders are characterized by a desire to scratch excessively, which harms the skin and delays its recovery. Researchers have tried to elucidate why excessive scratching occurs. For example, it is known that gender is a risk factor to most dermatologic diseases. Specifically, there are twice as many women with pruritic dermatological diseases compared to men.1,2 Also, women scratch more than men2 and burning process and itch sensations occur differently than in men, although no differences in specific differential pathways in the primary afferent nerves have been found.3

Together with gender differences in dermatologic diseases, increased evidence has also pointed to the importance of emotional factors in the onset and evolution of dermatologic conditions. For example, experimentally induced negative affect has been associated with increased sensitivity to itch.4 Also, perceived stress is known to be a vulnerability factor for dermatological diseases5 and itch symptoms.6 Research suggests that, as emotional tensions occur, itching and scratching increase.7 Congruent with the above, higher rates of emotional problems are found in dermatologic disorders.8 For instance, approximately one third of patients with dermatologic disorders also shows signs of psychiatric comorbidities.9 Emotional factors might also help understand gender differences in dermatologic diseases. For example, a study with 1037 patients with chronic pruritus revealed that female patients had a greater psychological burden compared to men.2 Being a female appears to be related to poorer emotional well being which, in turn, co-occurs with scratching. The question is why do women present more emotional problems and scratch behaviour?

The fact that scratch, emotional disturbance, and gender are related suggests that there might be a common underlying factor. Interestingly, personality styles are independently related to the three. First, emotional reactions and maladaptive behaviour are influenced by personality.10 In fact, personality styles have proven to be excellent predictors of health-related behaviours and emotional functioning in patients with multiple medical conditions.11–13 Second, gender differences in personality are well known. For example, research has shown that women are more other-nurturing, hesitating, and submissive than men.14 Finally, personality differences between patients with chronic itch conditions and healthy individuals have been found.15 In fact, personality styles are argued to help explain the fluctuations of skin disease by influencing emotional distress and scratching behaviour.16 Despite the above, it remains unclear whether personality styles can explain the co-occurrence of gender and emotional differences in patients with dermatologic diseases associated with chronic scratching.

Lichen Simplex Chronicus (LSC) is a prototype of a psychodermatologic disorder in which scratching is central. Patients with LSC cause or maintain inflammation (lichenification) of the skin by continuous and intense scratching, which in turn increases itch. Congruent with most psychodermatologic conditions, there are more women than men with LSC.7 Also, this disease is associated with increased psychopathology.17 In fact, its association with psychological factors is such that some psychodermatologists suggest that LSC is an emotional disorder with skin manifestations.18

The objective of the present investigation is to test whether personality styles can help to understand the higher prevalence of women and emotional problems in Lichen Simplex Chronicus, a dermatologic disease caused by scratching. We expect to find gender differences in personality styles among patients with LSC. A secondary goal is to explore whether these differences also exist between patients with LSC and healthy individuals. We hypothesize that differences in personality characteristics will occur when comparing patients with LSC and healthy individuals. Specifically, we anticipate that female patients with LSC will be more oriented to others, conforming, and focused on emotions than male participants with the disease. We expect that these characteristics will also stand out in LSC patients when compared to healthy individuals with the same gender.

103 patients diagnosed with LSC (Mage=47.13 years, range 13–84, 31.1% men) and 1184 healthy-normal controls (Mage=37.60 years, range 18–65 years, 45.7% men) were included in the study.

In the light of our results, there are personality differences between male and female patients with LSC, and also when they are compared with healthy individuals. Some, personality styles that are more frequent in females might be relevant risk factors for the chronic course of LSC. For example, women with LSC showed an increased tendency to be guided by feelings and emotions rather than by objective information when coping with stress. Surprisingly, they reported frequently hiding their negative emotions in order to cooperate and be in agreement with others. Congruent with these findings, previous research has revealed that women suppress the expression of emotions that they consider to be inconsistent with their gender role,21 mainly aggression.22 Most importantly, the use of this coping seems to reduce the ability to solve interpersonal conflicts,23 possibly by increasing physiological arousal, and subjective states of emotional distress.24 The above seems to hold true for patients with LSC, who present increased emotionality, difficulties in regulating their emotions and high levels of psychopathology.

Support for a stronger relationship between tension and scratching for women comes from those studies showing that emotional distress and psychopathology are associated with itching and scratching, and the link is stronger for women.25,26 A relationship between stress and negative emotions is well established. For example, stressful situations have been associated with numerous negative emotions (i.e. anger, anxiety and depression). In LSC, scratching might be one form of reducing stress. Even though this is arguably a maladaptive form of coping with stress, the use of such coping efforts in front of stress is not new. Self-mutilation, for example, is a well-known form of passive coping.27 These findings suggest that intense scratching, as shown in LSC, could act as a mild form of self-aggression. This might be one way of coping with stress in the absence of a better strategy to deal with emotional tension and increased arousal. Because personality styles tend to remain stable, when these styles are maladaptive scratching may become chronic.

Our results suggest that the aforementioned pathway might be especially relevant for females. Personality differences in our study might explain, at least to some extent, the higher prevalence of women with chronic scratching. Interestingly, some of these differences also occurred in men with LSC, although only partially and in lower magnitude. For example, men with LSC were more other-oriented, less dissenting, more dutiful, and less complaining compared to healthy males. Therefore, these personality styles might not only be risk factors for the LSC in women, but for men. Another important finding in our study was that some personality differences between LSC patients and healthy individuals were gender-specific. While men differed in cognitive styles, women mostly differed in motivational styles. The components of interpersonal styles in which LSC patients and healthy individuals differed depend on gender too. This makes us think that different pathways might be intervening in chronic scratching, at least in LSC.

In the previous paragraph we noted that certain personality styles might be considered to be risk factors for LSC only in males. For example, men with the disease prefer objective information and other people's opinions than their own intuitions and thoughts for guidance (realistic vs. imaginative and externally vs. internally focused). In addition, LSC males are more traditional and systematic in the way they gather information, in opposition to creative and novelty seeking (conservation vs. innovation). In line with this, they report following traditional social standards (unconventional) and being very stable in the way they think, feel and behave (dissatisfied). In this sense, a research has revealed that men tend to be more rigid in the way they think and behave, and this rigidity is associated with psychopathology.28 This might explain why this personality profile was more prominent in males with LSC in our sample.

This study certainly has some limitations. First of all, we used a cross-sectional design, which prevents us from drawing causal conclusions. That is, even if we found personality differences between LSC patients and healthy individuals, we cannot be sure that these personality styles are responsible for the onset of pathology. However, prospective research has shown this might be the case for many diseases.29 Moreover, even if emotional reactions involved in LSC are partly attributable to certain personality styles, the relation between these and scratching remains unexplored. The fact that certain personality styles were more prevalent in people who scratch does not necessarily mean that one caused the other. For example, negative affective states (such as anxiety, depression or anger), a possible confounding variable, was not measured. In addition, the severity of the lesion, economic status, family disturbances, etc., could also trigger or maintain scratching behaviour and should be taken into account in future studies. It is also important to note that, although LSC is a good model of chronic scratching, our findings are not necessarily generalizable to other dermatological conditions. Another limitation of the current investigation is that the control group used for personality comparison was a sample collected in a previous investigation in which the existence of dermatologic or mental problems was not assessed. While acknowledging this shortcoming, the sample assessed in the validation of the Millon Inventory of Personality Styles used a large population representative of the general population of Spain19; therefore, the present results may serve as indicators of personality differences between patients with LSC and people from the general population in Spain.

In summary, the present study suggests that personality styles should not be overlooked in the context of LSC, both in males and females. Our results suggest that certain adaptive styles increase the likelihood of behavioural responses (i.e. scratching) to stress through experiencing stressful situations and using maladaptive emotional regulation strategies (i.e. emotional suppression of unexpressed tension). As the specific mechanisms through which psychological variables influence the desire to scratch remain speculative, more studies addressing gender differences in personality should be carried out in dermatologic patients with chronic scratch behaviour. Moreover, we recommend assessing personality, especially in women, in order to detect patients with a higher risk of developing chronic scratching conditions. We suggest that the evaluation of personality should help to guide the treatment of patients with dermatologic conditions in which scratching is important.

The authors declare that they have no conflict of interest.