Itchy Skin at Night (Nocturnal Pruritus): Causes and Treatments

Itchy skin at night or Nocturnal Pruritus is a sensation that drives the urge to scratch the skin during night time. This condition can either, consciously prevent people from falling asleep due to an incessant drive to scratch the skin or lead to unconscious itching of the skin, causing sleep disturbances or make people awake to notice excoriated areas on the skin! As many times, people suffering from nocturnal pruritus are not aware to the extent they are scratching while asleep, further contributing to aggravated cutaneous inflammation. Thus, leading to sleep disturbances and diminished quality of life.

As per well-documented reports, reduced quality of sleep causes adverse effects on human performance, increased irritability, daytime drowsiness, eating disorders, impaired functioning and psychological issues (such as depression, loss of focus, agitated behaviour and lack of sexual desire). Poor quality of sleep in children with nocturnal itching has been linked to unfavourable neurocognitive, behavioural and physiological conditions such as poor academic performances, inability to focus, obesity, short stature, reduced immunological response, hypertension and hyper activeness.

Nocturnal itching is a common condition occurring as a result of natural bodily phenomenon’s, dermatological ailments, certain irritants or medications. However, in rare cases, it could also be a sign of severe health conditions.

Causes

The causative mechanisms for nocturnal itching are vague and are yet not completely understood. Both, dermatological and non-dermatological factors contribute to nocturnal itching. These constituting factors are enlisted below:

• Circadian Body Clock: The circadian body clock monitors the hormonal activities and chemical processes in the body. During night time, various factors tend to vary contributing to mild or serious itching to the skin. These are:

1. Increase in skin temperature and blood flow to the skin: As per the circadian body clock, core temperature of the body tends to be maximum in the evening and minimum in the morning. The temperature tends to vary across various stages of the sleep.

Thus, at particular stage of the sleep, termed as ‘NREM’ (Non-Rapid Eye Movement), the hypothalamic temperature is minimised and the heat is dissipated, resulting in vasodilation and increased blood flow. This phenomenon intensifies itching of the skin.

1. Increase in Cytokine levels during night time, which are responsible to co-ordinate immune response can result into more inflammation. As several types of cytokines have been known to induce itching.
2. Cortico-steroids (hormones that enable to reduce inflammation) are at peak throughout the day and tend to decrease during night time, thus, slowing down the anti-inflammatory response. This results into worsening of the itch associated with nocturnal pruritus.
3. The levels of Prostaglandin tend to elevate at night, (hormones which help in modulating inflammation, that facilitate skin repair). The disrupted levels of prostaglandin in patients suffering from Nocturnal Pruritus have shown to aggravate the itching.
4. During night time, the skin-barrier function is active that results into alterations. Thus, the Trans-Epidermal Water Loss (TEWL) or sweating tends to increase at night, which is a measure of skin-barrier integrity. And this impairment in barrier function causes the skin to itch by providing entry to pruritogens.

• Dust Mite Allergens: Nocturnal Pruritus is generally associated with the parasitic infestations, including scabies and bed bugs. The pre-dominant nocturnal itching present in scabies caused by the mites (Sarcoptes Scabiei) partially explains the fact that mites tend to be more active at night. Also, feces secreted by the mites consist of protease, that stimulate the Protease-Activated Receptors (Pruritic receptor), resulting into itching due to associated infections. Additionally, the immune response against the scabies mite stimulates the lymphocytes, resulting into release of several cytokines. Thus, the post scabetic itching could be caused by the activation of immune response as a defence against the mite antigen.

Bedbugs that hide near the beds, electric sockets or places that are dark and warm are also known to cause night-time itching, as they tend to be active at night. Bed bugs are prone towards warmth and carbon-dioxide. Thus, the exhaled carbon-dioxide from humans make them prey to their bites, resulting into intense itching and excoriations.

• Menopause/Pregnancy: Menopausal women tend to have itchy skin due to hormonal changes. During menopause, estrogen levels tend to decline. Estrogen is vital in maintaining skin health, as it keeps the skin moisturised by producing natural oils and collagen. Collagen is a protein that maintains firmness and elasticity of the skin. The declininirg level of natural oils and collagen make the skin dry and thin, resulting into itchiness. Severity of itching can range from mild to severe, that can lead to sleep disturbances.

During pregnancy, as the blood flow increases, it is common for women to experience itching. Moreover, skin of the abdomen is stretched, which causes it to itch. While most of the itching is a common phenomenon during pregnancy, severe itching is associated with an underlying liver condition (Intrahepatic Choletasis of Pregnancy)/Obstetric Choletasis. This is a liver ailment that causes disruption of bile flow, resulting into accumulation of bile in the body. Thus, causing intense itching throughout the body, that tends to worsen at night.

• Cancer: Itchy skin (pruritus) could be the first indication of cancer. The different types of cancer that involve the skin/the mucosal membranes/or that have metasized to the skin are more prone to itchy skin. Also, other conditions such as build-up of bile salts, or substances secreted by a tumor or by the body in response to tumor can cause irritation to the skin resulting into itching. The hormonal fluctuations cauised due to cancer and cancer therapies (radiation therapy/immunotherapy drugs) can cause liver inflammations or allergic reactions resulting into itching.
• Skin Disorders: Nocturnal pruritus tends to be highly prevalent in dermatological conditions such as Prurigo Nodularis, Atopic Dermatitis, Brachioradial Pruritus, Chronic Idiopathic Urticaria and Psoriasis. However, majorly, the dermatological conditions such as Atopic Dermatitis (AD) and Psoriasis are known to cause nocturnal pruritus. AD is characterized by disrupted epidermal barrier that facilitates the entry of different pruritogens. Due to a complex interactive networking between keratinocytes, cutaneous nerves and immune cells, several molecules and cytokines are released that cause inflammation and pruritic conditions. Thus, patients suffering from AD were reported to have sleep disturbances and premature sleep awakening resulted due to pruritus. Additionally, Melatonin (hormone produced by the pineal gland that helps in maintaining the sleep cycle/circadian rhythm) dysregulation can also cause nocturnal itchiness.

Psoriasis is a chronic inflammatory skin condition resulting due to impaired immune system. Patients suffering from Psoriasis have disruptions with heat dissipation and thermoregulation. Thus, due to problems with thermoregulation and aletred itch during nighttime in combination, can impact sleep quality. Other skin conditions such as fungal infections (athlete’s foot, pinworm infections) or eczema also can lead to nocturnal itching.

• Aging: Elderly adults tend to have dry skin due to declining lipids, reduced production of sweat, sebum and collagen. The excessive skin folds in geriatric poupluation provides a less surface area to interact with water, resulting into impairment in immune response and declining barrier repair. Thus, resulting into nightime itching (Senile pruritus) causing sleep disturbances.

The other factors that cause nocturnal pruritus are psychological conditions (such as stress, anxiety or severe depression), allergies to chemicals/dyes/fragrances, sunburns, kidney/liver failure, iron deficiency anemia, thyroid problems, medications (such as antibiotics, antifungals, analgesics/narcotics), HIV (Human Immunodeficiency Virus), health conditions affecting the nervous system (such as diabetes, shingles or multiple sclerosis), hay fever, asthma and chicken pox.

Home remedies and preventive measures

Nocturnal itching can be minimised by following certain home therapies without medicinal treatment in following ways:

• Taking cool/lukewarm baths before going to bed. Moisturisers, Unscented soaps, Baking soda (Sodium Bi-carbonate) or Colloidal oatmeal should be used.
• Glycerin based moisturisers (such as Cetaphil, Eucerin or CeraVe) that are free of oil/alcohol should be opted. Natural ointments/creams containing Vitamin E/Aloe vera should be applied to the skin before going to bed
• Application of cold compress (such as cold/damp cloth) to the skin before bed-time
• Keeping the bedroom free of insect infestations (such as bed bugs, fleas or ants) and pets before going to bed
• Drinking chamomile or peppermint tea (free of caffeine) before going to bed
• Air in the bedroom can be moistened by running a humidifier
• Wearing gloves/mittens to prevent scratching and further irritation to the skin
• Comfortable, loose fitting clothes are to be wore before going to sleep, enabling the skin to breathe

Other preventive measures to minimise nocturnal pruritus include:

• Drinking adequate water to keep the skin hydrated
• Warm baths/showers or saunas should be avoided before bed time to prevent elevated body temperature and loss of moisture
• Opting for clothes made out of natural fibre (such as Cotton)
• Before going to sleep, avoid consumption of alcohol/caffeine that can intensify blood flow to the skin
• Any rigorous activities that tend to increase the body temperature or blood circulation to the skin should be avoided
• Use of scented, coloured cosmetics or beauty treatments should be avoided before bedtime
• Bedsheets should be changed regularly

Treatment

As itch tends to be a common cutaneous symptom, diagnosing and managing it is considerably difficult. As pruritus could be a cause of different skin conditions or several other factors, differential diagnosis is narrow. Therefore, primary step is to find the cause for the same. If it occurs due to any medicinal reactions, changing the drug can help minimise the itching. Nocturnal itching is generally due to organic causes, as somatoformic itching does not cause patient to wake up during night time. Over-the-counter drugs or certain medicines advised by the doctor can help treat existing symptoms or prevent the recurrence of the same.

• Products such as Corticosteroid creams containing not more than 1 to 2.5 percent active Hydrocortisone can be applied to reduce inflammation.
• Anti-allergic/Anti-histamine medicines can help relieve some symptoms of pruritus. Over-the-counter anti-histaminic drugs such as Benadryl (Diphenhydramine), Allegra (Fexofenadine) and Zyrtec (Cetirizine) can help minimise inflammation. However, only non-sedative anti-histamines give effect in some patients.

Sedative anti-histamines (ones that cause drowsiness) such as Chlorpheniramine are no longer advised to manage pruritus. However, certain antidepressant tablets upon being prescribed by the doctor can be taken during night time to avoid getting disturbed in sleep due to itching.

• Supplements that contain hormone (Melatonin), which plays a major role in the sleep cycle that helps promote sleep, can be taken during night time.
• Over-the-counter anti-itch creams that contain moisturisers (such as Crotamiton or Lauromacrogols) can be applied before bedtime. Doxepin drug in cream form can be used upon prescription by the doctor before falling asleep.

The other medicines that can help reduce or treat night-time itching include:

• Cortico-steroid creams/pills that are more stronger than over-the-counter medicines, can help minimise redness or itching caused due to inflammation.
• Antidepressant medicines such as Silenor (Doxepin) and Remeron (Mirtazapine) can be used to treat nocturnal itching caused due to psychological factors (such as depression/anxiety).
• Immunosuppresants (such as Hecoria, Gengraf and Neoral) can be taken to reduce inflammation that are topical calcineurin inhibitors.
• Phototherapy that uses Ultraviolet light treatment/wavelength can help to minimise immune response and inflammation. Thus, enabling to reduce the itch-scratch cycle associated with pruritus.
• Hormonal replacement therapy (particularly Estrogen based) can help minimise itching associated with dry skin.
• Gabapentin and Pregabalin are prescribed for treating anxiety and conditions of insomnia.
• In order to reduce the effect of itchiness associated with insomnia, Kappa opiod agonists are prescribed.

However, chronic or prolonged night-time itchiness are required to be examined by the doctor, particularly if they are not associated with existing health conditions. It is paramount to consult the physician if nocturnal itching tends to be uncomfortably bothersome causing sleep disturbances and interfering with routine activities. Therefore, immediate medical attention should be sought for unexplained itchiness lasting for more than two weeks or has not improved even after taking precautionary measures. Also, dry skin that tends to affect the whole body accompanied by other symptoms such as changes in skin colour, fatigue, fever or sudden weight loss should be a bought to medical notice.

Now, Say No to Itch and yes to Sound Sleep!

References

1. https://www.mdpi.com/1422-0067/17/3/425
2. https://www.ncbi.nlm.nih.gov/pubmed/29943835
3. https://www.medicaljournals.se/acta/content/abstract/10.2340/00015555-0280