Ch6: pruritus and dysaesthesia Flashcards
1
Q
Things to look for on assessment when dealing with itch
A
- Xerosis
- Dermographism
- Butterfly sign: difficult to reach area spared
- Mid-upper back involvement: primary skin disease/back scratching device
- Lymph nodes
- Scabies
2
Q
2007 Classification - International Forum for the Study of Itch:
A
- Inflamed skin
- Non-inflamed skin
- Chronic secondary scratch induced lesions
3
Q
Ix for pruritus
A
- Skin scrapings
- Biopsies may be helpful
- DIF of peri-lesional
- Initial bloods:
- FBC, UEC, LFT
- LDH
- Fasting BSL
- Thyroid
- ESR, CRP
- Additional other
- IgE
- Iron studies
- BP
- HbA1c
- PTH + CMP
- Viral hepatitis, HIV
- Serum tryptase, histamine
- u/A
- Porphyrin screen
- EPG, IEPG
- Imaging:
- CXR, CT
- LN USS
- Other
- Patch testing
- Prick testing
- Cancer screen
4
Q
Main ddx for itch
A
- Inflamed dermatoses
- Eczema: mediators are neuropeptides - substance P, CGRP, neurotrophic factors, opioid receptors, IL-2, IL-31, endothelin 1, PAR2
- Psoriasis: substance P, nerve growth factor, IL-2
- Infestations
- Scabies: begins 3-6 weeks after first time infestation
- Infections
- Neoplastic
- CTCL: IL-31 implicated. Rx strategies include gabapentin, mirtazapine, opioid antagonists
- Genetic/naevoid
- Other
- Dermatoses induced by pruritis associated scratching or rubbing
5
Q
Prurigo nodularis epidemiology
A
Middle aged women
6
Q
Prurigo nodularis clinical
A
- symmetric, extensor aspects of extremities
- Butterfly sign
- Flexures not affected
- Morphology: dome-shaped papulonodules with central scale, erosion, ulceration, can get verrucous or fissured
- If crust but no papulonodules: prurigo simplex
- Often secondary to primary disease: atopic dermatitis, xerosis, systemic illness, psychological
7
Q
What happens to nerves in prurigo nodularis
A
More nerve density and thickening
8
Q
Prurigo nodularis differentials
A
- Perforating disorder
- Pemphigoid nodularis
- Hypertrophic lichen planus
- Hypertrophic lupus erythematosus
- Scabies
- Insect bites
- Dystrophic EB
- Multiple KAs
9
Q
Prurigo nodularis histology and staining
A
- Histo:
- epidermal hyperplasia
- thick, compact hyperkeratosis
- erosions
- fibrosis of the papillary dermis with vertically arranged collagen fibers, increased fibroblasts and capillaries
- perivascular or interstitial mixed inflammatory infiltrate
- Immunostain:
- Pan-neuronal marker PGP 9.5 –> highlights that there is an increase in density of dermal nerve fibers
10
Q
Prurigo nodularis treatment
A
- treat underlying issues
- topical anti-pruritics: menthol, pramoxine, polidocanol, palmitoylethanolamine, capsaicin (0.025-0.3% 4-6 times daily), calcipotriol, calcineurin inhibitors
- oral anti-histamines
- topical steroids under occlusion
- IL-steroids
- phototherapy
- excimer laser treatment
- Compulsive behaviour:
- SSRIs and TCAs
- Thalidomide: 50-200 mg daily
- Gabapentin, pregabalin and neurokinin-1 receptor blocker aprepitant
- Opioid blockers: naloxone, naltrexone, butorphanol (intranasal)
- Cyclosporin?
11
Q
LSC - what is it
A
Epidermal hypertrophy secondary to chronic scratching
12
Q
LSC epidemiology
A
Adults
13
Q
LSC clinical
A
- well-defined plaques with exaggerated skin lines, leathery appearance, coalescing papules, hyperpigmentation, varying degrees of erythema
- solitary or multiple
- sites: posterolateral neck, occipital scalp, anogenital region, shins, ankles, dorsal aspects of hands, feet and forearms
14
Q
Risk factors for LSC
A
xerosis, atopy, psoriasis, anxiety, OCD, localized neuropathic itch
15
Q
LSC histology
A
compact hyperkeratosis, acanthosis with irregular elongation of rete ridges, hypergranulosis, vertically oriented collagen bundles
16
Q
LSC treatment
A
- same as prurigo nodularis
- topical and intralesional steroids
- Repeated application of hydrocolloid dressing
- topicals: lidocaine, capsaicin, antipruritic agents
17
Q
Scalp pruritus
A
- can occur in absence of any objective changes
- middle aged, with stress and fatigue
- Rx: topical steroids, antipruritic agents
18
Q
Pruritus ani epidemiology
A
- 1-5% of population
- M:F 4:1
19
Q
Causes of pruritus ani
A
- primary
- pruritis in the absence of any cutaneous, anorectal or colonic disorder
- causes: diet such as excessive coffe intake, personal hygiene, psych
- secondary
- chronic diarrhoea –> if on chronic antibiotics –> liquid stools with pH of 8-10 –> lactobacillus
- faecal incontinence/anal seepage
- haemorrhoids
- anal fissures or fistulas
- rectal prolape
- cutanoues issues
- STDs
- malignancy
- infestations –> pinworm infection in kids is common
- radiation therapy
- neuropathic –> nerve compression, back issues
20
Q
Rx of primary pruritus ani
A
- Sitz baths, cool compresses, hygiene, fragrence free toilet paper or bidet –> then dry with blotting or a fan
- application of zinc oxide
- mild steroid cream –> can increase
- topical calcienurin inhibitors
21
Q
Pruritus vulvae and scroti
A
- solely psychogenic in only 1-10%
- worse at night, repeated rubbing leads to lichenification
- evaluation same as pruritis ani
- Acute pruritis: candidiasis, ACD, ICD
- Chronic: dermatoses, malignancy, atrophic vulvovaginitis
- Scrotal pruritis also been associated with lumbosacral radiculopathy
22
Q
What is aquagenic pruritus
A
- sensation occurs within 30 minutes of water contact, irrespective of temperature or salinity, and lasts for up to 2 hours
- begin on lower extremities then generalize, spares the head, palms, soles and mucosae
- unsure how it works –> elevated dermal and epidermal levels of Ach, histamine, serotonin and PgE2 has been seen
23
Q
Causes of aquagenic pruritus
A
- Primary
- Secondary
- Urticaria - cold, dermographism, cholinergic, aquagenic
- Haematoloigic malignancy: PCV (ruddy complexion), haemochromatosis (diffuse hyperpigmentation), Hodgkin, MDS, essential thrombocythemia
- Infiltrates: mastocytosis, HES
- Drugs: anti-malarial, clomipramine, testosterone induced erythrocytosis
- Aquagenic pruritis of the elderly
24
Q
Aquagenic pruritus treatment
A
- Alkalinization of bath water to pH of 8 with baking soda
- Light therapy
- Capsaicin - can decrease symptoms but long-term use not ideal
- Systemic: cyproheptadine, cimetidine, cholestyramine
- Secondary: anti-histamines
25
Q
Pruritus in scars cause
A
- scar remodeling can last 6 months - 2 years
- pruritis with wound healing is common, can be prolonged
- due to:
- physical stimuli - mechanical stimulation of nerve endings
- chemical stimuli: histamine, vasoactive peptides and prostaglandins
- C fibres, both myelinated and unmyelinated, will contribute to itch perception
26
Q
Pruritus in scars treatment
A
- emollients
- Topical and intra-lesional steroids
- Silicone gel sheets
- Oral anti-histamines
- Oral pentoxifylline
27
Q
Post-thermal burn pruritus risk factors
A
deep dermal injury, female, psychological distress
28
Q
Post-thermal burn pruritus treatment
A
- emollients
- topical anaesthetics
- massage therapy
- bathing in oiled water
- morphine
- oral gabapentin more effective than cetirizine
29
Q
Fibreglass dermatitis
A
- manufacturing or construction
- hands, and other non-covered sites involved
- cutaneous: looks like scabies, eczema, folliculitis, urticaria
30
Q
Renal pruritus epidemiology
A
- rare in children
- otherwise doesnt correlate with age
- haemodialysis –> has decreased over years, likely secondary to improvement in dialysis methods
- for those getting 3X a week, the pruritus peaks in the evening after 2 days without dialysis, is relatively high during dialysis and is lowest the following date
31
Q
Renal pruritus aetiology
A
- Overall, it is poorly understood
- histamines not really thought to be part of the process
- ?Accumulation of compounds that cross the dialysis membranes slowly
- Parathyroid gland activity –> however no correlation observed with PTH levels
- Pruritus does not correlate with xerosis, SC hydration or sweat secretion
- Peripheral neuropathy –> may be manifestation of this
- Opioid accumulation
- IL-31 has been reported –> topical tacrolimus food for this
32
Q
Renal pruritus management
A
- Assess:
- Serum PTH –> treat if appropriate
- Quality of dialysis: Kt/V: urea clearance multiplied by dialysis time divided by volume of urea distribution is >1.2
- If itch persists - gabapentin after each dialysis can be tried
- General skin care measures
- Topicals
- Capsaicin
- Gamma-linoleenic acid - 2.2% QID
- Pramoxine
- Cromolyn sodium
- Systemic
- First line
- Gabapentin 100-300 mg daily
- Pregabalin - 25-75 mg daily
- Phototherapy
- Second line
- Naltrexone - 25-100 mg daily
- Nalfurafine 2.5-5 microg PO or IV (K-opioid receptor blocker)
- Others:
- Charcoal
- Montelukast
- Cromolyn
- Thaldiomide - 100 mg daily
- Ketotifen
- Doxepin
- Sertraline - 25-100 mg daily
- Pentoxifylline
- Lidocaine
- EPO
- Cholestyramine
- Ultimate: renal transplant
- First line
33
Q
Causes of cholestatic pruritus, and pathogenesis
A
- Most common:
- Primary biliary cholangitis
- Primary sclerosing cholangitis
- Choledocholithiasis
- Bile duct carcinoma
- Cholestasis
- Chronic HCV
Aetiology
- ubnknown
- ?bile acids –> but not always elevated
- increased opioidergic neurotransmission or neuromodulation in the CNS may contribute
- More recent studies indicate: lysophosphatidic acid (LPA) and autotaxin (ATX, lysophospholipase D) are associated with increased itch
34
Q
Cholestatic pruritus clinical
A
- generalized, migratory and not relieved by scratching
- worse on hands, feet, body regions constricted by clothing
- worse at night
- can be an early symptom that develops years before any other manifestation of the liver disease
35
Q
Cholestatic pruritus treatment
A
- Treat underlying cause
- Intra-hepatic cholestasis of pregnancy: UDCA (ursodeoxycholic acid) reduces itch and serum bile acid levels - due to improvement of hepatobiliary secretion - 13-15 mg/kg or 1 g daily
- first line for others:
- Cholestyramine 4-16 g po daily- binds bile acids in the small intestine and faecally excretes them
- Second line:
- rifampin: 300-600 mg daily reduces ATX expression on a transcriptional level
- Third line
- Naloxone 0.2 microg/kg/min with 0.4 mg IV bolus
- Naltrexone 25 mg BD PO
- Nalfurafine 2.5-5 microg daily
- Fourth line:
- Sertaline 50-100 mg daily
- Last: liver transplant
- Other options:
- Phototherapy, bright light therapy
- Nalmefene: mu opioid blocker, start at 2 mg on day 1, 5 mg day 2, 10 mg day 3 –> can incr to 120 mg daily
- Butorphanol nasal spray: 1-2 mg daily, also opioid blocker
- Ondansetron
- Paroxetine
- Dronabinol - cannabinoid B1 receptor agonist
- Phenobarbital - 2-5 mg/kg daily
- Stanozol
- Propofol
- Lidocaine
- Thalidmoide
- Procedural
- Nasobiliary drainage
- Other methods to remove pruritic factors: plasmapharesis, plasma separation, anion adsorption
36
Q
Iron deficiency pruritus clinical
A
Generalized or localized
Particularly perianal and vulvar region
Improves with iron supplementation
37
Q
PCV associated pruritus
A
- Aquagenic pruritus can precede diagnosis by several years, eventually affects 30-50% of patients –> should always consider this diagnosis in aquagenic pruritus
- 95% of patients with PCV have a JAK2 mutation –> results in activation and agonist hypersensitivity in basophils –> may result in the aquagenic pruritus
- MOA: ?platelet aggregation –> histamine release –> pruritus
38
Q
PCV pruritus treatment
A
Rx: aspirin, can provide relief for 12-24 hours, alternatives: phototherapy, SSRI (small series), JAK inhibitor ruxolitinib, IM inferon-alpha, anti-histamines
39
Q
Paraneoplastic itch
A
- Paraneoplastic itch: systemic reaction to the presence of a tumour or a haematological malignancy, neither induced by the local presence of cancer cells nor by tumour therapy
- Most commonly seen with myeloproliferative neoplasms, Hodgkin disease, NHL
- Recalcitrant pruritus should be evaluated for an underlying malignancy
- Intensity and extent do not correlate with tumour involvement
- MOA:
- ?toxic products from necrotic tumour cells entering circulation
- tumours producing chemical mediators
- allergic reaction to tumour specific antigens
- increased proteolytic activity
- histamine release
- Biliary obstruction
- Central nervous system invovlvement
- From treatments - surgery, chemo, radio, etc
40
Q
Itch associated with Hodgkin disease and MOA
A
- Noctural generalized pruritus, with chills, sweating and fever –> some argue should become a B symptom
- Severe, persistent pruritus is a poor prognostic factor
- MOA:
- Reed-Sternberg cells secrete IL-5 –> eosinophils
- Histamine release, leukopeptidases, bradykinin
- Hepatic involvement?
41
Q
Hodgkin disease treatment
A
- Lymphoma treatment
- Topical steroids
- Oral mirtazapine
- Aprepitant –> NK1 receptor blocker
42
Q
Thyroid changes that result in itch
A
- hyperthyroidism –> severe generalized
- Hypothyroidism –> dry skin –> asteatotic eczema with pruritus, can also get local or generalized pruritus
43
Q
Diabetes itch
A
- generalised pruritus
- can get localized: genital and peri-anal areas –> diabetic women with poor glycaemic control
- predisposition to candidiasis
- Diabetic neuropathy –> burning and prickling sensations as well
44
Q
Pruritus in HIV and AIDs
A
- occasionally can be presenting symptom
- HIV: develop pruritic dermatoses such as pruritic papular eruption, eosinophilic folliculitis, severe seb derm, psoriasis, scabies, insect bite reactions, etc
- Intractable pruritus and HIV viral load has been observed
- Immunologic markers associated with pruritus in HIV patients:
- elevated IgE
- peripheral hypereosinophilia
- Th2 type cytokine profile
45
Q
Pruritus in HIV treatment
A
- topical steroids and antihistamines
- anithistamines with anti-eosinophilic potential may be better –> cetirizine
- UVB
- ART –> can help, but sometimes can flare skin conditions
- Thalidomide: 100-300 mg/day
46
Q
Medications that cause pruritus (remember liver, skin, nervous system, mediators)
A
- Any medications that affect the liver:
- Cholestasis: oestrogens, captopril, sulfonamides, erythromycin
- Hepatotoxicity: panadol, steroids, minocycline, augmentin, halothane, phenytoin, sulfonamides
- Any medications that affect the skin:
- Xerosis: retinoids, tamoxifen, beta-blockers, clofibrate, beta-blockers
- Phototoxicity: psoralens
- Any medications that affect the nervous system:
- Opioids
- Recreational drugs
- Anti-depressants: SSRIs
- Any medications that result in increased mediators:
- ACEI –> increased bradykinin
- NSAIDs –> increased leukotriene
- Hitamine –> betahistine
- Other:
- EGFR inhibitors
- PD-1s
- TK inhibitors
- Chloroquine –> MRGPR stimulation
- Starch –> deposition
- Idiopathic: clonidiine, gold salts, lithium, bleomycin
47
Q
Dysaesthesia definition
A
unpleasant abnormal sensation
48
Q
List all the types of localized neurologic pruritus
A
- Trigeminal trophic syndrome –> face
- Brachioradial pruritus –> arm
- Radial dorsal antebrachial cutaneous nerve
- intermittent pruritus or burning pain on the dorsolateral aspects of the forearms and elbows
- degenerative osteoarthritis on x-ray in 50%, rarely associated with spinal cord tumour
- UV light exacerbates, may report relief with ice
- Cheiralgia paraesthetica –> dorsum of hand
- Mononeuropathy of the superficial branch fo the radial nerve
- Numbness, tingling, burning
- Trauma or pressure –> tight watch, etc
- Notalgia paraesthetica –> medial scapular borders
- Posterior rami T2-6 –> degenerative change in 60% of affected patients. These nerves take a right angle course through the multifidus spinae muscle –> entrapment and injury
- Rarely associated with MEN Type 2a (childhood or adolescence)
- Hyperpigmented patch due to chronic rubbing (correlates with dermal melanophages)
- Focal macular amyloidosis
- Meralgia paraesthetica –> lateral thigh
- Lateral femoral cutaneous nerve –> pressure on this as it passes under the inguinal ligament
- Allodynia associated as well
- Risk factors: obesity, pregnancy, prolonged sitting, tight clothing, carrying heavy wallets in trouser pockets, lumbar radiculopathy
- Digitalgia paraesthetica –> fingers
- Digital nerves of fingers (can be toes too)
- Trauma or pressure
49
Q
Neurologic pruritus treatment
A
- topical capsaicin 0.025-0.3% 3-6 times a day for >4-6 weeks
- Topical anaesthetics or steroids
- Oral gabapentin or pregabalin
- Acupuncture
- Imaging
- Referral to ortho and neurology
- Physical therapy, nerve blocks, surgical decompression
50
Q
Burning Mouth Syndrome (Orodynia) epidemiology and aetiology
A
- Epi: middle-aged or older adults, F>M
- Aetiology:
- Malignant lesion
- Exogenous: ill-fitting dentures, any medications that cause xerostoma
- Infectious: candidiasis
- Papulosquamous: contact dermaitits
- Metabolic: iron, zinc, folate, B12
- Endocrine: diabetes, hypothyroidism, menopause
51
Q
Burning Mouth Syndrome (Orodynia) clinical
A
- Bilateral: anterior 2/3 of tongue, palate and lower lip
- Types:
- 35%: absence of symptoms on awakening, gets worse throughout the day
- 55%: constant
- 10%: days of remission that follow no identifiable pattern
52
Q
Burning Mouth Syndrome (Orodynia) treatment
A
- Treat underlying cause
- TCAs, low dose benzos, gabapentin
- Anti-depressant
- Topicals: capsaicin, lidocaine, anaesthetics, tetracycline, hydrocortizone, Maalox
- CBT and alpha-lipoid acid 600 mg daily
53
Q
Burning scalp syndrome
A
- diffuse, burning pain, pruritus, numbness, tingling of the scalp
- Secondary causes: seb derm, LPP, ACD, ICD, DLE
- Assoc: depression and anxiety
- Rx: gabapentin, TCA, topical capasaicin
54
Q
Dysaesthetic anogenital pain syndromes
A
- most common cause: haemorrhoids and fissures
- Other: trauma, infection, testicular torsion, malignancy
- Syndromes:
- Levator ani: intermittent burning pain or tenesmus of the rectal or perineal area, aggravated by sitting or elimination
- Procatlgia fugax: stabbing pain
- Coccydynia: localized to the coccyx, intermittent or persistent pain
- Male genital pain syndrome: intermittent, continuous or episodic pain during penetration, urination, ejaculation, etc
- Koro syndrome: acute anxiety, fear of genitalia are inwardly retracting and pain
55
Q
Trigeminal neuralgia
A
- Recurrent paroxysms of sharp pain - seconds to minutes, trigeminal distribution
- Unilateral (right sided more common)
- can occur several times a day
- can be triggered by teeth, eating, talking
- Secondary causes: MS, trauma, tumour
- MRI: 80-90%: compression of trigeminal nerve root by a vascular loop
- Rx: carbamazepine in 70-90% works well, oxcarbazepine, lamotrigine, baclofen, botox, surgical: microvascular decompression and ablation
56
Q
Trigeminal trophic syndrome
A
- Self-mutilation triggered by dysaesthesia together with hypaesthesia from damage to the sensory portion of the trigeminal nerve
- Nasal tip is spared, as it is supplied by the external nasal branch of the anterior ethmoidal nerve
- clinicl: small crust that develops into crescentic ulcer
- Underlying nerve damage: iatrogenic due to therapeutic ablation for trigeminal neuralgia, stroke, HSV, trauma, craniofacial surgery
- Ddx:
- malignancy
- infections
- inflamamtory: granulomatosis with polyangiitis, PG
- Factitial disease
- Rx:
- carbamazepine
- gabapentin, amitryptyline
- pimozide
- protective barriers
- surgical repair of the defect with innervated skin flaps
57
Q
Complex regional pain syndrome
A
- upper extremities, particularly hands, involved
- disproportionate pain
- accentuated pain and sensation, can have vasomotor dysfunction, hypertrichosis, hyperhidrosis, nail dystrophy, motor dysfunction
- Refer to neuro
58
Q
Congenital Insensitivity to pain and related conditions
A
- basically have cuts etc everywhere and increased risk of infection because they don’t feel pain
- Stains for neuronal markers: PGP-9.5 –> absence of innervation to sweat glands, BV, arrector pili muscles
Morvan disease, Riley-Day syndrome., CIP with anhidrosis
