Pruritus and dysesthesia Flashcards
What three classifications should be made for pruritus?
- Affecting diseased (inflamed) skin? -Affecting non-diseased (non-inflamed) skin
- Presenting with chronic secondary scratch-induced lesions
What are some red flags which may suggest underlying disease as cause of pruritus?
Chronic or generalized pruritus, age older than 65, abnormal physican exam findings such as organomegaly, LAD, etc.
What are some components of a history that suggest a benign course?
Younger age, localized sx’s, acute onset, involvement limited to exposed areas, clear association with sick contact or recent travel.
What 6 categories of dermatologic disease should be thought of in pruritus?
Inflammatory, infestation/bits/stings, infections, neoplastic, genetic/nevoid, other
What is prurigo nodularis?
Chronic repetitive scratching/picking 2/2 pruritus or dermatologic disease or psych condition that causes reactive papules/nodules
Clinical of prurigo nodularis?
Multiple pruritic, dome-shaped, firm hyperpigmented papulonodules that may have a central scale/crust/erosion. The ulcerations are distributed symmetrically on extensor extremities with sparing of hte mid-back (butterfly-sign)
Where is prurigo nodularis most commonly seen?
Middle-aged adults with underlying dermatologic/psychiatric disorder and occasionally in children with atopy
Treatment of prurigo nodularis?
SSRIs/TCAs for underlying psychologic condition, doxepin, MTX, thalidomide/lenalidomide, topical capsaicin, calcipotriene, liquid nitrogen, and cyclosporine
What is lichen simplex chronicus?
Hypertrophy of the epidermis as a result of chronic, habitual rubbing or scratching of the skin.
Clinical of lichen simplex chronicus?
Clinically appears as well-defined plaques with lichenification, hyperpigmentation and varying erythema Favors posterior neck, occipital scalp, anogenital region, shins, ankles, and dorsal hands, feet, forearms. Predisposing factors include xerosis, atopy, stasis dermatitis, anxiety, obsessive–compulsive disorder, and pruritus related to systemic disease. Broader, thinner lesions than prurigo nodularis but w/ same itch-scratch cycle perpetuating the condition
Treatment of lichen simplex chronicus?
treat underlying systemic or psychiatric illness if present; avoidance of scratching/rubbing; topical/ intralesional agents (corticosteroids and calcineurin inhibitors); topical antipruritics (menthol and pramoxine), antihistamines, and behavioral therapy
What is scalp pruritus?
May be primary: lacks skin lesions; a/w anxiety and dpression Or, secondary to dermatoses: psoriasis, seb derm, and folliculitis
Treatment for scalp pruritus?
emollients and topical steroids; tar or salicylic acid shampoos, and low dose doxepin
Epidemiology of pruritus ani?
Pruritus of anus and perianal skin (1%–5% population); male ≫ female
Clinical of pruritus ani?
Skin appearance: normal to severely irritated (erythema/crusting/lichenification, erosions/ulcerations)
Cause of pruritus ani?
Primary pruritus ani: pruritus in absence of cutaneous, anorectal, or colonic disorder; may be due to dietary factors, poor personal hygiene, or psychologic disorders Secondary pruritus ani: due to irritation from stool or hemorrhoids or fissures, primary cutaneous disorders, infectious or infestations, previous XRT, neoplasms, or contact allergy
Tx for pruritus ani?
reduce irritation w/ sitz baths, cool compresses, meticulous hygiene, mild topical steroids (class 6 or 7) or topical calcineurin inhibitors, and treatment of underlying disorder
What is pruritus scroti/vulvae?
Acute or chronic pruritus of scrotum or vulva; worse at night; lichenification secondary to repeated rubbing/scratching
Pathogenesis of pruritus scroti/vulvae/
acute: infections, allergic or irritant contact dermatitis; chronic: secondary to dermatoses, malignancy, atrophic vulvovaginitis, lumbosacral radiculopathy, irritation, or psychogenic (1%–7% patients)
What is aquagenic pruritus?
Severe pruritus or burning pain after water contact, irrespective of water temperature; within 30 min of contact with no visible skin changes; lasts up to 2 hrs; spares head, palms/soles, and mucosae
Pathogenesis of aquagenic pruritus?
usually secondary to systemic disease (e.g., polycythemia vera) or other skin disorder
Treatment fo aquagenic pruritus?
alkalization of bath water to pH 8 with baking soda, oral antihistamines, phototherapy, and capsaicin; clonidine and propranolol for aquadynia
How common is post-burn pruritus?
85% of burn patients experience pruritus
What is the pathogenesis of pruritus in scars/
Sequence of physical and chemical stimuli as well as nerve regeneration A disproportionate number of thinly myelinated and unmyelinated C-fibers in immature or abnormal scars may contribute to increased itch perception. Physical stimuli include direct mechanical stimulation of nerve endings during scar remodeling Histamine, vasoactive peptides such as kinins, and prostaglandins E1/E2 act as chemical mediators and may account for a “chemogenic” pruritus.
Tx for pruritus a/w scar?
Treat with ILK and/or silicone gel sheets, oral pentoxifylline (400 mg 2–3 times daily)
Tx for fiberglass pruritus?
talcum powder, or tape
What percentage of pt’s w/ no primary dermatologic cause but have pruritus have an underlying systemic condition (presenting to a derm office)
14-24%
What percentage of patients with kidney disease have pruritus?
>50% of patients with CKD have pruritus and 80% of those on dialysis
When is the pruritus 2/2 CKD worse?
Pruritus peaks @ night after 2 days w/o dialysis, is relatively high during tx and is lowest during the day following dialysis
Is pruritus in those with CKD a prognostic indicator?
Renal pruritus is an independent marker of mortality for pt’s on hemodialysis
What is the mechanism of pruritus in CKD?
Mechanism unclear. No relationship between the plasma histamine level and severity of pruritus -Peripheral neuropathy affects up to 65% of patients who receive dialysis -Pruritus may be a manifestation of a neuropathy? -Caused by loss of itch-inhibiting CGRP-expressing neurons in the papillary dermis potentially
Do antihistamines work in pruritus of CKD?
No
Treatment options for those with pruritus of CKD?
Topical capsaicin, topical y-linolenic acid, topical pramoxine, activated charcoal, gabapentin, pregabalin, UVB phototherapy, cholestyramine, naltrexone, ondansetron, nalfurafine, ondansetron, nalfurafine, ketotifen, cromolyn sodium, montelukast, thalidomide, lidocaine, erythropoietin
What are the most common entities which cause biliary pruritus?
primary biliary cirrhosis, primary sclerosing cholangitis, obstructive choledocholithiasis, carcinoma of the bile duct, chronic hepatitis C/ viral hepatitis
Description of biliary pruritus?
Generalized, migratory pruritus worse at night Typically worse on hands, feet, and body covered by clothing
Treatments for biliary pruritus?
**Cholestyramine** Ursodeoxycholic acid (ursodiol) Rifambin Naltrexone Naloxone Nalmefen Propofol Thalidomide
Hematologic diseases a/w pruritus?
Iron deficiency and polycythemia vera
Clinical of iron deficiency pruritus?
Generalized or localized pruritus in the perianal or vulvar region
What percentage of those with polycythemia vera have pruritus?
30-50%
When in the disease does aquagenic pruritis show up in polycythemia vera/
Anytime, may precede the development of PCV even.
Pathogenesis of pruritus in polycythemia vera?
platelet aggregation causing serotonin and histamine release; mutation in JAK2 → constitutive activation and agonist hypersensitivity in basophils
What is the treatment for pruritus in polycythemia vera?
ASA 300mg qd to tid provides relief for 12-24 hours UVB or PUVA phototherapy Antihistamines
Clinical of pruritus that may be concerning for malignancy?
persistent, unexplained, intractable pruritus without primary skin lesion
What is the most common malignancy a/w pruritus?
Hodgkin disease
pathogenesis of pruritus in Hodgkin disease?
Proposed that pruritus should be added as a “B” symptom for this disease IL-5 from Reed-Sternberg cells causes eosinophilia which may be related to pruritus?
What is the treatment for pruritus in Hodgkin disease?
Treat malignancy, topical corticosteroids, oral mirtazapine
What percentage of patients with non-Hodgkin lymphoma have pruritus?
10%
What types of leukemia can have pruritus?
In general rare in leukemia, but can occur in CLL and hypereosinophilic syndrome
What should be checked lab-wise for pruritus in the genital or perianal areas, especially in women?
HgbA1c/glucose DM has been a/w w genital and perianal pruritus if poorly controlled
What type of thyroid disease is more likely to cause pruritus?
Hyperthyroidism more than hypothyroidism.
What are some pruritic dermatologic conditions associated with HIV?
Pruritic papular eruption, eosinophilic folliculitis, severe seborrheic dermatitis, psoriasis, scabies, drug eruptions, xerosis, and acquired ichthyosis. Also, insect bites are significantly more inflammatory and pruritic in the HIV-infected population.
What may contribute to the pruritus seen in HIV infected individuals?
Increased serum IgE, peripheral hypereosinophilia, and a Th2-type cytokine profile
Treatment of pruritus in HIV?
Thalidomide 100-300mg/day
What medications can cause pruritus via cholestasis?
Chlorpromazine, erythromycin estolate, estrogens (including OCP’s), captopril, sulfonamines
What medications can cause pruritus via hepatotoxicity?
Acetaminophen, anabolic steroids, isoniazid, minocycline, amoxicillin-clavulanic acid, halothane, phenytoin, sulfonamides
What medications can cause pruritus via sebostasis/xerosis?
Beta-blockers, retinoids, tamoxifen, busulfan, clofibrate
What medications can cause itch via unknown causes?
Chloroquine, clonidine, gold, lithium
What is dysesthesia?
describe an abnormal, unpleasant sensation Symptoms: pruritus, burning, tingling, stinging, anesthesia, hypoesthesia, tickling, crawling, or pain
What typically causes a dysesthesia?
Typically caused by nerve trauma, impingement, or irritation
Most common types of dysesthesia seen by dermatologists?
Sensory (mono)neuropathies that are most often brought to the attention of dermatologists are notalgia paresthetica and brachioradial pruritus.
What is notalgia parasthetica?
Pruritus, pain, burning, cold-sensation, tingling or numbness over the medial scapular borders
What disease is notalgia parasthetica a/w?
MEN2A (especially if onset is in childhood or adolescence)
Etiologies of notalgia parasthetica?
Entrapment of the dorsal segments of T2-T6, which supply cutaneous innervation to the area between the scapula and vertebral columns Serratus anterior dysfunction
Characteristic PE findings of notalgia parasthetica?
A characteristic finding on physical examination is a hyperpigmented patch due to chronic rubbing of the affected area
Tx for notalgia parasthetica?
Lidocaine 2.5% and prilocaine 2.5% (EMLA) cream BID Systemic: gabapentin, oxycarbazepine, amitriptyline Transcutaneous electrical nerve/muscle stimulators NBUVB
What is brachioradial pruritus?
Pruritus, burning, tingling over dorsolateral forearms/elbows which is frequently bilateral
Etiology of brachioradial pruritus?
Sun exposure Cervical spine disease
Tx of brachioradial pruritus?
Sun protection Topical: corticosteroids, doxepin, amitriptyline 1%/ketamine 0.5% cream Surgery (if cervical spine issue)
What is the “icepack” sign in brachioradial pruritus?
Brachioradial pruritus is often improved by applying something cold. Applying an icepack makes it go away… this is apparent enough that it can be pathognomonic for it.
What is meralgia paresthetica?
Entrapment or damage to the lateral femoral cutaneous nerve (LFCN) causing paresthesia of the lateral and anterolateral upper thigh
What patients most often get meralgia paresthetica?
patients that tend to have pressure in the inguinal area: Most prevalent in pregnant, diabetic, or obese patients Those who wear tight belts
What is Digitalgia paresthetica?
Sensory neuropathy affecting digital nerves of the fingers and less often the toes
Cheiralgia paresthetica
sensory mononeuropathy of the superficial branch of the radial nerve numbness, tingling, or burning involving the dorsoradial aspect of the hand and proximal thumb
What is burning mouth syndrome?
Burning mucosal pain of the anterior two thirds of tongue, palate, and lower lip bilaterally (sparing buccal mucosa and floor of mouth) without primary lesions
What part of the tongue is affected in burning mouth syndrome?
Anterior 2/3
Who most often gets burning mouth syndrome?
Middle-aged to elderly women
Tx for burning mouth syndrome?
antidepressants, benzodiazepines, gabapentin, antifungals, antibiotics, and “magic mouthwash” combinations
What procedure must be asked about in patients with scalp dysesthesias?
Facelift or browlift procedures
What is a trigeminal trophic disorder?
Trigeminal nerve injury leads to self-inflicted ulceration which is typically unilateral and involves the nasal ala or V2 branch of the trigeminal nerve
Destruction of what structure is related to symptoms in trigeminal trophic disorder?
Frequently occurs after treatment for trigeminal neuralgia w/ ablation of Gasserian ganglion
What branch of the trigeminal nerve is affected by the trigeminal trophic disorder?
It can be any branch!
Differential dx for trigeminal trophic disorder?
malignancy, Wegener granulomatosis, infectious etiologies,brown recluse bite, pyoderma gangrenosum, and factitious dermatitis
Tx for trigeminal trophic disorder?
- Physical barrier–> keep nails short, wearing gloves at night, wear thermoplastic face mask, night time arm splinting
- Transcutaneous electrical nerve stimulation unit
- Medications: gabapentin, carbamazepine, pregabalin, pimozide, amitriptyline
- Surgical: Paramedian forehead graft
What is complex regional pain syndrome/reflex sympathetic dystrophy?
Clinical presentation dependent on stage of disease Most common symptom is burning pain of upper limbs that is aggravated by movement or friction; affected skin may become shiny, cold, and atrophic Five major components: pain, edema, autonomic dysregulation, alterations in motor function, and dystrophic changes
What are the five components of complex regional pain syndrome/reflex sympathetic dystrophy?
Five major components: pain, edema, autonomic dysregulation, alterations in motor function, and dystrophic changes
Treatment for complex regional pain syndrome/reflex sympathetic dystrophy?
directed toward interrupting autonomic nervous system; often ineffective trophic changes
