7 &8 - Pruritis and dysethesia + psychocutaneous disease

Question 1

What criteria are used for the diagnosis of acquagenic pruritus?

Answer 1

1. severe pruritus that occurs after water contact irrespective of water temperature or salinity.
2. pruritus within minutes of water contact without visible skin changes.
3. exclusion of chronic skin diseases.

Question 2

What disease may aquagenic pruritus precede?

Answer 2

Polycythemia rubra vera. Aquagenic pruritis may precede this by several yers.

Question 3

What conditions is cholestatic pruritus most commonly associated with?

Answer 3

• primary biliary cirrhosis
• primary sclerosing cholangitis
• obstructive choledococholithiasis
• carcinoma of the bile duct
• chronic hep C

Question 4

what are the clinical features of cholestatic pruritus?

Answer 4

• generalised and migratory
• worse on the hands, feet and body regions constricted by clothing
• pronounced at night.

Question 5

What is the treatment for pruritus in polycythemia vera?

Answer 5

• aspirin 300 mg three times daily
• UVB or PUVA therapy
• intramuscular interferon a
• oral H1/H2 receptor antagonist

Question 6

How does puritus present in diabetes mellitus?

Answer 6

• generalised usually
• localised pruritus in the genital and perianal areas is common in diabetic women and is associated with poor glycemic control.

Question 7

what is the clinical presentation of brachioradial pruritis

Answer 7

intermittent pruritus of the arm superior to the elbow.

- usually exacerbated by UV light.

Question 8

What treatment options are available for brachioradial pruritus?

Answer 8

• NSAIDs
• topical capsaicin
• gabapentin 600 - 1800 mg/day

Question 9

what are the clinical features of notalgia paresthetica?

Answer 9

Focal, intense pruritus over the medial scapular borders. Accompainied by pain, paresthesias or hyperesthesias.

• well- circumscribed hyperpigmented patch in the affected area.

Overlap with macular amyloidosis.

Question 10

How does trigeminal trophic syndrome present clinically?

Answer 10

• small crusts that develop into a crescenteric ulcer and gradually involves the cheeks and upper lip with sparing of the nasal time.
• self-mutilation are triggered by parasthesias and dysesthesias that occur after damage to the sensory portion of the trigeminal nerve.

usually trigeminal neve damage is iatrogenic from ablation of the gasserian ganglion.

Question 11

What is the treatment of choice for delusions of parasitosis?

Answer 11

• pimozide

Question 12

What is the treatment of choice in neurotic excoriations?

Answer 12

• 5% doxepin cream

- doxepin 100 mg/day should be the goal

Question 13

What is the epidemiology of trichotillomania?

Answer 13

• peak onset is in childhood and starts around the age of 8 in boys and 12 ingirls
• usually there is a female preponderance.

Question 14

What is seen histologically in trichotillomania (key features)?

Answer 14

• pigmented hair casts
• trichomalacia
• empty hair follicules
• perifolliular lyphocytes,plasma cells or neutrophils are spare or absent.
• vertical fibrous tracts

Question 15

What is seen histologically in prurigo nodularis?

Answer 15

• focal hyperkeratosis
• acanthosis
• papillomatosis
• irregular proliferation of the epidermis.

Question 16

What are the differential diagnosis of a prurigo nodularis?

Answer 16

• acquired perforating dermatosis
• pemphigoid nodularis
• keratoacanthomas
• granular cell tumours
• SCCs.
• hypertrophic lichen planus.

Question 17

What is the management of prurigo nodularis?

Answer 17

consider doxepin.

For localized leisons:

• topical potent corticosteroids under occlusion
• intralesional corticosteroids
• topical capsaicin 0.025% 4-6 times daily.
• cryotherapy

For generalised lesions:
nbUVB
PUVA
cyclosporin 3- 4.5 mg/kg/day
thalidomide 100 -300 mg/day
Goeckerman therapy.

Question 18

What are the clinical features of lichen simplex chronicus?

Answer 18

• usually seen in adults (unusual in children)
• hyperpigmented, lichenified leatherpy plaqes
• usually on the occiput and nucal areas in women and the perineum and scrotum in men.
• wrists, extensor surfaces of forearms and lower legs involved.