Prader-Willi Syndrome And Skin-Picking Behaviours

Overview

Prader-Willi syndrome (PWS) is a rare genetic condition known to be one possible explanation for life-threatening obesity in children and adults. It affects the development of the hypothalamus, an important part of the brain responsible for the hormonal control of growth, appetite, reproductive function, body temperature, sleep and behaviour.¹

PWS patients are known for their particular behavioural profile usually focused on food-seeking, food hoarding and eating, characterised by mental rigidity, anxiety, temper tantrums, obsessive-compulsive and self-injurious behaviours, including skin picking.² 

Occasional skin picking is not an unusual behaviour in people, but it becomes a problem when it causes evident skin damage that leads to distress and affects everyday functioning, escalating, from a common behaviour to a mental health disorder, called skin picking, or excoriation disorder. 

This article aims to bring understanding to the skin-picking behaviour in Prader-Willi patients, uncovering its particularities, causes, diagnosis, and treatment options. 

What is Prader-Willi syndrome?

Prader-Willi syndrome (PWS) is a genetic condition caused by missing genes on chromosome 15 and is considered the most common genetic cause of severe, life-threatening obesity in children and adults. PWS syndrome affects one in 10,000 to 30,000 born babies. Genetic errors have visible consequences on patients’ appearance, physical and mental development, and behaviour.^1,2,3,4

PWS syndrome is visible at birth, or shortly after, the baby presents distinctive facial features and low muscle tone (hypotonia), also known as “floppy baby”. Affected babies are very lethargic, and have feeding difficulties at the beginning, but later on, they acquire an insatiable appetite and develop severe obesity due to overeating, if left untreated. PWS patients also present other behavioural characteristics, such as skin picking, temper tantrums, anxiety, obsessive-compulsive disorder, autism, or psychosis. PWS also causes hormonal deficiencies regarding the growth hormone and the sexual hormones, leading to growth, puberty, and reproductive problems.^2,3 

For more information about PWS syndrome, see this article: What is Prader-Willi syndrome?

What is skin-picking behaviour and skin-picking disorder?

Skin-picking behaviour is present when a person suffers from excoriation (or skin-picking) disorder. Also known as “dermatillomania”, the skin-picking disorder is a mental health condition that affects people compulsively rubbing, scratching, digging, or squeezing at their skin causing lesions, infections, and even scarring. Some patients do it without even realising it, others are aware of the behaviour but cannot stop it. Skin-picking behaviour is a form of body-focused repetitive behaviour, and hair pulling (trichotillomania ) and nail biting (onychophagia) are also in this category. As many as 1 in 20 people suffer from skin-picking disorder. 

According to the Diagnostic and Statistical Manual of Mental Disorders, patients diagnosed with this condition cause evident skin injuries resulting from their skin-picking behaviour. They are trying to stop themselves from continuing the behaviour or try to decrease the intensity of the behaviour, and they feel significant embarrassment, and shame, and their normal everyday functioning is affected. People suffering from skin-picking disorder often also have other mental health problems, like anxiety or depression. 

The patients don’t have obsessions and are not concerned about their appearance, but they feel tension or anxiety and these are relieved by skin picking, and they often feel gratification afterwards. Skin-picking is not obsessive-compulsive disorder (OCD).

Treatment of skin-picking disorder implies medication and talk therapy. The medication is prescribed by a psychiatrist, and it is used to treat other psychiatric disorders. In severe cases, when people have extensive skin damage, they might require surgery, such as skin grafting. As far as medication is concerned, to treat or to prevent lesion infection, antibiotics are prescribed. 

To learn more about skin picking disorder, see this article: What is skin picking disorder?

Prader-Willi and skin-picking behaviour 

Prader-Willi patients have a characteristic behavioural profile, visible from childhood. Besides their eating and food obsessions, they present anxiety, temper tantrums, obsessive-compulsive behaviour, rigidity to change, and skin-picking behaviour. They also present a high risk of developing psychiatric illnesses, such as psychosis, depression and anxiety disorder. The “PWS profile” also includes intellectual disability, which majorly impacts the overall functioning of the patients.^5,6,7 

About 60 to 85% of PWS patients show severe skin-picking behaviour. They scratch, pick, poke, and dig at skin irregularities or abnormalities so severely, that they develop open wounds which can lead to localised or whole-body infections, and skin scarring.⁸ 

Skin picking is a form of self-injurious behaviour and causes more problems that require clinical attention, than the other abnormal behaviours encountered in Prader-Willi patients. Self-injury behaviours affecting Prader-Willi patients are skin-picking, nose-picking, hand-biting, head-banging, hair-pulling and rectal-picking. PWS patients pick the legs, the head, and the arms, as preferred body sites for self-injury. More specifically, the area around the nose and the mouth, and the shin area of the legs.⁹

What are the causes of skin picking in Prader-Willi patients?

PWS patients with paternal deletion of the genes located in the 15q11-13 region are more prone to skin-picking behaviour than those with maternal uniparental disomy (mUDP) as far as the genetic cause is concerned.^4,7,9 

Skin-picking behaviour can also be explained by something happening inside PWS patients’ brains, a process called interoceptive disturbance. Interoception is a term to define the fact that we can sense the signals our body sends us from within, for example how we know when we are hungry. In PWS patients, the hunger perception is distorted, and they have an insatiable appetite that untreated, leads to morbid obesity. But there might also be a problem with the internal perception of itch and pain, and this impacts their skin-picking behaviour.

Due to the interoceptive disturbance, they might feel a stronger itch signal, and after skin picking, a more intense sense of relief. The whole experience of itch-pick-relief might be distorted, and because they might have higher pain thresholds, they may continue skin-picking even after causing themselves extensive skin damage. The interoceptive disturbance might provide an explanation for the skin-picking behaviour, which might feel so rewarding that would be very difficult to resist.⁸

What are the skin-picking particularities of the patients?

Skin-picking behaviour usually is noticed in PWS patients when they are about 5-6 years old, along with other behavioural problems, such as temper tantrums and repetitive behaviours.⁷ 

The skin-picking behaviour worsens with time in Prader-Willi patients, and is the most severe in young adults, around the age of 20 to 30 years, and later on in life, it ameliorates. Children and teenagers affected by Prader-Willi present some gender differences related to this behaviour, with people assigned female at birth (AFAB) being more affected than people assigned male at birth (AMAB).^5,10 Other studies show that the self-injurious behaviour doesn’t improve with age, and skin-picking will remain stable in Prader-Willi patients.¹¹

Prader-Willi patients prefer some particular skin-picking locations, which most frequently are the anterior part of the legs and the front of the face.^9,10 Around 15% of the affected teenagers and adults also engage in rectal picking.¹⁰ Rectal picking behaviour might be difficult to discover in PWS patients, but proof might be found on the underwear, sheets, or on the patient’s hands.⁷ 

Patients carrying the paternal deletion in their genes might present more body locations for skin-picking behaviour than the patients carrying the maternal uniparental disomy.⁹

Other skin-picking behaviours are nail or skin biting, or nail picking. Patients can also pull out their hair, including the eyebrows and eyelash hairs.^7,11 

How is skin-picking behaviour diagnosed in Prader-willi patients? 

Skin-picking behaviour might often go unnoticed by parents or caregivers, and only the skin marks secondary to the behaviour might bring the PWS patient to the doctor. Skin scarring, colour changes, and infected wounds can be identified during a dermatological clinical assessment. The dermatologist, or other doctors, such as a paediatrician, can also identify the skin picking behaviour when the patients present a history of nose bleeds or rectal bleeds, which could be consequences of the nose or rectal picking behaviour. A psychiatrist or a paediatric psychiatrist would determine the diagnosis, identify other possible concomitant mental health problems, and would also prescribe medication as needed.¹²

What are the treatment options?

Medication

Due to the lack of extensive research on the use of psychotropic medication regarding psychiatric illness for Prader-Willi patients, they are given the standard treatment indicated for the symptoms and behaviours, but with caution, and the medication is used in combination with adequate psychiatric support and behavioural therapy. As far as medication is concerned, antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), anticonvulsants (to treat epilepsy), and antipsychotics (to treat psychosis), are used to manage skin-picking behaviour. Studies showed that fluoxetine and topiramate could reduce skin-picking behaviour in PWS patients. As with any other medication, adverse reactions, or undesired effects might emerge secondary to psychotropic treatment, so the close monitoring of a psychiatrist is necessary.^9,10

In case the skin picking causes a local skin infection, topical antibiotics are prescribed for a short, determined, period of time, along with wound dressing, and applied bandages. These measures may discourage skin-picking behaviour.^10,13

Recombinant growth hormone therapy (GHT) is a hormone replacement therapy used in PWS patients to improve their height, metabolism, body muscle composition, bone mineral density, and even cardiovascular health. This treatment might also help improve their behaviour particularities, including skin-picking, but further research is needed.¹⁴

Therapy

Psychiatric care is important for PWS patients and requires close monitoring in order to adequately find the right treatment for the specific symptoms and behaviours. Talk therapy (psychotherapy ) used is cognitive-behavioural therapy (CBT), acceptance and commitment therapy (ACT), group therapy, habit reversal training (HRT), and others, and it requires a long-term approach and consistency, to modify the behaviour.¹⁰

Support groups

Social connections provide significant support for PWS patients and their families, improving the overall outcome of the patients.

• Prader-Willi Syndrome Association UK
• International Prader-Willi Syndrome Organisation (IPWSO) 
• Medical Home Portal
• Prader-Willi Syndrome Association USA
• Foundation for Prader-Willi Research

Summary

Prader-Willi syndrome is a rare genetic disorder affecting the development of the brain and the hypothalamus. PWS patients have a particular behavioural profile, focused on food, due to their insatiable appetite. They frequently show self-injurious behaviour, picking, poking, scratching, and digging at their skin, continuing the behaviour even when they develop wounds. 

The process called “interoceptive disturbance” might be an explanation of the skin-picking behaviour in PWS patients, because their internal perception of itch, pick, and pain is distorted, and they appear to feel deep relief and reward after skin-picking, making it so difficult to resist and control. 

Skin-picking behaviour in PWS patients is sometimes difficult to identify and diagnose. Patients can initially be treated by the dermatologist for the immediate care of an infected wound secondary to skin picking, and further be evaluated by a psychiatrist. 

PWS patients receive the standard treatment for skin-picking behaviour, involving medication and therapy. Psychotropic agents, used in depression, or epilepsy, appear to reduce the behaviour, but psychotherapy, such as CBT, ACT, and HRT, is also very important and requires consistency and a long-term approach. 

Social connection is beneficial for the overall outcome of the patients, and support groups might hold great value to the patients and their families in dealing with Prader-Willi syndrome.