Pruritis

Question 1

Pruritis

How is an itch experienced?

Answer 1

An itch is the result of peripheral nerves being stimulated by histamine and possibly neurotransmitters also

Question 2

Pruritis:

Why is it so common in elderly?

Answer 2

Very common in the elderly.

Skin changes as part of age.
Impairment of:
-barrier
-immune response
-thermoregulation
-sensation

Reduction in:

• subcutaneous fat
• blood supply
• sebaceous and sweat gland activity

Question 3

Pruritis:

Causes?

Answer 3

Dermatological:
Xerosis - dry scaly lower extremity
Dermatitis - atopic, contact, asteototic (Winter itch)
Fungal - tinea corporis
lice
scabies
psoriasis
urticaria

Systemic:

Haematological issues

• iron deficiency anaemia
• polycythaemia Vera
• Macroglobuminaemia

Infection

• HIV
• shingles
• measles

Medications

• diuretics
• lipid modifying therapy
• ACEi
• anti-epileptic drugs
• allopurinol

Psychiatric

• parasitosis
• OCD
• somatic disorders

Renal
-CKD 50%

Cholestasis

• cirrhosis
• hepatitis
• cholangitis

Neurological

• CVA
• MS
• tumours

Neoplastic 30%

• hodgkins lymphoma
• chronic lymphocytic leukaemia
• multiple myeloma

Endocrine

• hypo/hyperthyroidism
• hyperparathyroidism
• diabetes (increased risk of fungal infections)

Question 4

Pruritis:

Approach?

Answer 4

1) Acute or chronic (6 weeks as cut off)
2) itch only OR
itch AND rash
3) sleep disturbed
4) medications, new, changed, OTC
5) Atopy history
6) constitutional symptoms
7) sick contacts

Examination:

• webbing, intertrigenous areas, genitalia
• distribution of itch (If dermatomal and no rash then is likely neuropathic)
• abdominal examination
• lymph node check

If thought to be systemic related then Investigate:

• CBE +/- film
• EUC CMP
• LFTs
• Ferritin
• fasting glucose
• TSH
• Chest X-ray
• serum electrophoresis
• (consider BBV screening when reasonable)

Question 5

Pruritis:

Management?

Answer 5

General:

• short cooler showers
• avoid prolonged heat exposure
• pat dry (avoid skin trauma in general)
• avoid wool clothing
• emollient regularly
• avoid soaps
• shorten fingernails to limit reservoir or trauma from scratching

Specifics:

1) cease offending medications if reasonable
2) Pharmacological
- treat underlying dermatological or systemic condition
- non sedating antihistamines
- menthol 1% in aqueous cream topically
- Ichthammol 1% (Egoderm) cream/ointment
- Pine tar (Pinetarsol)
- Urea 10% cream (Aquacare Hp)
- topical corticosteroid