Ch. 6- Pruritus and Dysesthesia Flashcards
Name 8 non dermatologic causes of itch
Systemic: Renal disease, Liver/biliary disease
Infections: HIV, Hep C (liver)
Metabolic: Thyroid disease, diabetes, iron deficiency, hemochromastosis, hyperPTH
Malignancy: Lymphoma and myeloproliferative neoplasms (e.g. PCV, essential throbocytosis, HES), paraneoplastic itch
Invisible derm: Celiac, BP, Dermatographism
Neurologic: peripheral or central causes
Psychocutaneous disorders
What are the 3 major groups of pruritis
(1) affecting diseased (inflamed) skin
(2) affecting non-diseased (non-inflamed) skin;
(3) presenting with chronic secondary scratch-induced lesions
What are the 6 major causes/categories of pruritus
dermatologic
systemic
neurologic
psychogenic
mixed
other/unknown
List the workup for someone with generalized pruritus NYD
H+P: Full skin exam, LAD, look at mid back for butterfly sign
Biopsy of any lesions + peri-lesional for DIF (celiac, BP)
Bloodwork:
CBC, lytes
Renal and liver, LDH
A1C, TSH
ESR/ CRP
Consider:
Infection: HIV, Hep B/C
Stool for O+P
Iron studies, PTH/Ca/Phos
Total IgE
Celiac testing, BP ab’s
Anti-mitochondrial/smooth muscle ab’s (PBC, PSC)
SPEP/UPEP
CXR or CT chest
Abdo/pelvis US
Spinal xray or Sri for localized itch
Age appropriate cancer screening
PAtch testing or SPT
IMO lower yield:
UA
5-HIAA urine
Serum tryptase/chromogranin A
What 2 types of CTCL are most likely to cause pruritus
Sezary
Folliculotropic
Name 4 treatments for pruritus in CTCL
Gabapentinoids
Opioids-naltrexone 50-150 mg
Aprepitant
Mirtazapine
Name 5 possible underlying causes for prurigo nodularis
Derm conditions:
-AD, xerosis
Systemic condition:
-Hepatic/renal disease, hyperthyroid, lymphoma
Psych:
-OCD, anxiety, stress
NAme 10 things on the ddx for PN
Perforating dermatoses
Hypertrophic LP
Scabies nodules
Pemphigoid nodularis
Hypertrophic DLE
Persistent insect bites
Pruriginous type of dominant dystrophic epidermolysis bullosa
KA’s and granular cell tumors
Name two changes in the nerves of PN
Hypertrophy and increased density dermal nerve fibres with concomitant reduction in epidermal nerve fibres/ epidermal small fibre neuropathy”
What is the difference between primary and secondary pruritus ani?
Primary - no clear underlying cause
Secondary - underlying cause
NAme 6 causes for secondary pruritus ani
chronic diarrhea
fecal incontinence/anal seepage
hemorrhoids
anal fissures or fistulas
rectal prolapse
primary cutaneous disorders (e.g. psoriasis, lichen sclerosus, seborrheic dermatitis, allergic contact dermatitis)
sexually transmitted diseases
infestations (e.g. pinworms)
previous radiation therapy
neoplasms (e.g. anal cancer)
What is the workup for pruritus ani
Evalute psychiatric causes
Consider testing for pinworm or O+P
Lactobacillus replacement if chronic diarrhea from abx
Patch testing
Rectosigmoidoscopy
What is the workup for pruritus ani
Evalute psychiatric causes
Consider testing for pinworm or O+P
Lactobacillus replacement if chronic diarrhea from abx
Patch testing
Rectosigmoidoscopy
+- Lumbosacral MRI–> nerve compression
Name 5 treatments for primary pruritus ani
Sitz baths
Perianal hygiene- water-moistened, fragrance-free toilet paper or a bidet
Barrier creams
TCS or TCIs
Name 2 causes of aquagenic pruritus
- Most often a cause, primary is uncommon
PCV
Aquagenic urticaria
How does aquagenic pruritus present?
Aquagenic pruritus presents with prickling, tingling, burning, or stinging sensations within 30 minutes of water contact, irrespective of its temperature or salinity, and lasts for up to 2 hours
Typically, symptoms begin on the lower extremities and then generalize, with sparing of the head, palms, soles, and mucosae
on examination, specific skin lesions are not seen.
The pathologic mechanism is unknown, although elevated dermal and epidermal levels of acetylcholine, histamine, serotonin, and prostaglandin E 2 have been described 1 .
Name 10 conditions that may result in sensation of pruritus with water
(excluding primary aquagenic pruritus)
Urticaria–> dermatographic, cholinergic, aquagenic, cold-induced
Mastocytosis
Hemochromatosis
Blood causes:
Hypereosinophilic syndromes
PCV
Hodgkin disease
Myelodysplastic syndromes
Essential thrombocythemia
Testosterone-induced erythrocytosis
Drug-related (e.g. antimalarials, bupropion, clomipramine)
Aquagenic pruritus of the elderly (xerosis may be subtle)
Name 4 treatments for scar associated pruritus
Topical steroids
ILK
Silicone gel sheets
Pentoxyfiline 400 2-3 times daily
What is one systemic treatment for post burn pruritus
Gabapentin
*others include topical anesthetics, colloidal oatmeal, bathing in oil, emollients
What is the pattern of pruritus in uremic pruritus for patients on HD
usually peaks in the evening after 2 days without dialysis, is relatively high during dialysis, and is lowest the following day
What is the cause of uremic pruritus
NOT elevated levels of urea. Poorly understood.
Dramatic improvement in some patients after parathyroidectomy but not no correlations with serum PTH, Ca or Phos.
No clear correlation with xerosis.
Possibly neuropathy, as 65% of patients on dialysis have neuropathy.
Increased levels IL-31
Therapeutic ladder for uremic pruritus (Bolognia)
Y-linolenic acid 2.2% QID
0.025% three to five times daily
Pramoxine
Cromolyn sodium
Gabapentin