Introduction
Treatment of chronic pruritus (CP) without rash is challenging. Figuring out the underlying cause of itching is the main step to get rid of this unpleasant sensation. Some patients may have chronic pruritus of unknown origin (CPUO). Treatment options of chronic pruritus without rash may include medical and physical treatment options.
General instructions
- Skin should be kept moist.
- Bathing recommendations:
- Bathing time should not exceed 20 min.
- Fragrance-free saops should be used.
- Limit use of soap to axillae and groin/perineum.
- Excessive bathing is not recommended,
- Use luke warm water not hot water.
- Moisturization
- Use a refrigerated emollient often helps considerably.
- Fragrance-free emollient BID to TID and especially after bathing.
- Baby oil BID to TID.
- Menthol 0.25%/camphor 0.25% in emollient BID to TID.
- Avoid all skin irritating products.
- Avoid wearing rough clothing, such as wool, over itchy areas
- Avoid wool and other rough fabrics.
- Patients should avoid overbathing and overdrying their skin with soaps and cleansers.
- Patients should always have trimmed fingernails.
- Scabies and drug induced pruritus should be excluded, both of them are curable.
- Studies have shown that behavioral therapy reduces the intensity of itch, participants learn to consciously suppress the reflex to scratch through distraction and habit reversal.
- Topical and systemic steroids should not be used except for steroid responsive dermatoses.
- Antihistamines should be used for histamine mediated dermatoses.
- Sedative antihistamines may be used for patients who complain of nocturnal itching and have sleep difficulities.
- Minimization of exposure to dust and heat as well as of stress and anxiety are benefcial.
Topical treatment options of pruritus without rash (mainly for localised pruritus)
- Cooling agents/counterirritants
- For example, Menthol, camphor, capsaicin.
- Emolients
- Urea may be applied in a 5% to 20% formula.
- Anesthetics
- Pramoxine 1% to 2.5% or lidocaine 1% to 5% is applied topically to the affected area not more than three to four times daily.
- Polidocanol 3%.
- Topical antihistamine
- Topical strontium chloride in a 4% concentration gel.
- Topical Capsaicin 0.025%
- four times daily with at least 3 to 4 ‐hour interval between applications.
- Topical cromolyn sodium.
- Topical amitriptyline, in combination with ketamine, has been successfully used for brachioradial pruritus.
- Cannabinoid receptor agonists.
- N‐palmitoyl ethanolamine.
- Topical doxepin 5% cream.
- Four times a day (for up to eight days)
- Risk of contact allergy.
- Botulinum toxin
- Reports showed Botulinum toxin to be effective in notalgia paraesthetica and lichen simplex.
- Botulinum toxin A (100 UI/vial) can be reconstituted with saline solution (0.9%), with a dose of 5 UI injected into the affected area.
- The antipruritic effect may remain for one week.
Systemic treatment options
- Sedating antihistamines
- Sedating antihistamines can be used during night time for sleep improvement.
- Caution should be taken in elderly patients.
- Hydroxyzine 25 mg three times day, diphenhydramine 50 mg/d.
- Neuromodulators:
- Gabapentin: 300-1800 mg/d.
- Pregabalin: 25-300 mg/d.
- Carbamazepine: 200‐mg dose twice daily for pruritus associated with multiple sclerosis, postherpetic neuralgia, and trigeminal atrophy.
- They are used mainly for CKD-associated pruritus and neuropathic CP.
- Common side events of gabapentinoids include dizziness, drowsiness, weakness, and nausea.
- Antidepressants:
- SSRIs
- Paroxetine 20 mg/day for 4-6 weeks, especially for paraneoplastic pruritus, psychiatric disease and polycythemia vera pruritus.
- Sertraline in cholestatic pruritus but with caution because severe cardiac side effects have been reported.
- FLuoxetine.
- Mirtazapine : 15 mg to 30 mg a day for at least four to six weeks.
- SSRIs
- Serotonin receptor antagonists
- Ondansetron: 4 mg to 8 mg twice daily for uraemic and cholestatic pruritus.
- Topisetron (5 mg/day).
- Granisetron (1 mg/day).
- Not recommended due to lack of evidence.
- Opioid antagonists/agonists
- Can be used for pruritus in chronic urticaria, AD, cholestatic pruritus and CKD-associated pruritus.
- Nalmefene (10 mg twice daily) and naltrexone (50– 150 mg /day).
- Naloxone, 1.6 mg/hour for four hours
- Nalfurafine has been used for Japanese patients with uremic pruritus.
- Common side effects include nausea, vomiting, headaches, and fatigue
- Severe side events, include ventricular tachycardia and paraesthesia.
- Other:
- Thalidomide (especially for prurigo nodularis): 50–300 mg/day
- Thalidomide is teratogenic and there is a dose-related risk of neuropathy.
- Not recommended due to side effects.
- Aprepitant (NK1 receptor antagonist)
- 3-day course of 125 mg/80 mg/80 mg repeated every two weeks or daily 80 mg.
- Common side effects of aprepitant include fatigue, diarrhoea, dehydration, low white cell count, and constipation.
- Thalidomide (especially for prurigo nodularis): 50–300 mg/day
- Serlopitant
- It can be given at 1‐mg and 5‐mg doses for six weeks.
- No evidence of adverse events.
- Nemolizumab (anti‐interleukin‐31)
- 60 mg SC every 4 weeks.
- Common side effects include peripheral oedema, nasopharyngitis, raised creatine kinase levels, and upper respiratory tract infection.
Physical treatment options
- Phototherapy
- It is indicated for generalised pruritus, especially in elderly pruritus patients or in case of systemic therapy is contraindicated.
- Phototherapy is effective in chronic kidney disease associated pruritus.
- Bath PUVA therapy and systemic PUVA have been founf helpful in aquagenic pruritus.
- UVB provided relief for pateints with HIV indued pruritus.
- The treatment is given in the form of three times a week for three months.
- Transcutaneous electronic nerve stimulation
- A series of 15‐ to 30‐minute sessions.
- Side effects include skin irritation, local erythema, and numbness.
- Acupuncture
- It includes 15‐ to 20‐minute sessions.
- It is relatively safe.
- The most common side effect is skin infection.