Essential Dermatology for GPs

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Essential Dermatology for GPs

• The Itchy Patient
• Lucy Scriven

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(No Transcript)
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• Itching may be due to an underlying skin
  condition
• Eczemas
• Scabies, lice, threadworms
• Psoriasis (sometimes)
• Insect bites
• Exanthems
• Lichen planus
• Nodular prurigo
• Bullous pemphigoid
• Polymorphic light eruption

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Whats this?

• Pompholyx

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• PLE

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• Bullous pemphigoid

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• Eczema

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• Lichen planus

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• Psoriasis

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• Scabies

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• Papular urticaria

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What if they are just itchy?
Pruritus Itchy skin in the absence of any
obvious dermatological condition

• Generalised Pruritus

• Localised Pruritus

• Medications
• Dermatological conditions with subtle signs
• Systemic disease
• Psychogenic
• Aquagenic pruritus
• Idiopathic

• Brachioradial pruritus
• Notalgia paraesthetica

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• Up to 50 of pts will have no clear cause
  idiopathic pruritus
• This should be a diagnosis of exclusion!
• So we need a logical approach to try to
  ascertain a cause.......

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• STEP 1 TAKE A CAREFUL HISTORY
• Onset, duration, pattern, effect on sleep, past
  history of skin disease, contacts, response to
  treatments so far
• Medications
• Opioids, Statins, ACEI, Digoxin
• Need to discontinue suspected drug for a few
  weeks if possible
• Systemic disease
• Liver disease, renal failure, haematological
  disorders, thyroid disease, paraneoplastic

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• Localised Pruritus 2 conditions which cause
  localised areas of itching / burning
• Brachioradial pruritus - around elbow and
  extensor surface of forearm
• Notalgia paraesthetica mid-scapular area
• Consider capsaicin cream
• thinly od increased to
• maximum qds over 2wks.
• Treat for 8 wks
• Or try gabapentin or low
• dose amitriptyline.

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• Aquagenic pruritus
• Patients complain of intense pricking itch on
  contact with water or change of skin temperature
• Do not develop a rash
• Responds poorly to antihistamines
• May respond to phototherapy

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• STEP 2 EXAMINE THE PATIENT CLOSELY
• Dry skin / asteototic eczema
• Common cause, especially in the elderly in winter
• Signs may be subtle
• FEEL the skin!
• Look closely for fine scale
• Excoriations
• Bruising
• Lichen simplex chronicus

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• Asteototic eczema

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• Excoriations

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• Butterfly distribution

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• Lichen simplex chronicus

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• Dermographic urticaria
• Should be reproducible

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• STEP 3 - ? SYSTEMIC DISEASE
• Liver disease, renal failure, haematological
  disorders (e.g. Iron deficiency anaemia,
  polycythaemia, Hodgkins lymphoma), thyroid
  disease, paraneoplastic phenomena, pregnancy
• Thorough history and examination to include
  checking for enlarged lymph nodes and
  hepatosplenomegaly

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• Screening investigations in pruritus
• Full blood count
• Ferritin
• CRP
• Routine biochemistry (UE, LFT, bone, glucose)
• Thyroid function
• Antimitochondrial antibody (1 biliary cirrhosis)
• Urinalysis
• Chest X ray
• Consider immunoglobulins and plasma
  electrophoresis in older pts

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• STEP 4 - ? PSYCHOGENIC
• Anxiety / depression can cause or be caused by
  pruritus, esp in older pts
• Delusions of parasitosis
• Patient is convinced that a parasite /
  infestation is living in their skin
• May bring inorganic matter to the consultation
• Excoriations often seen but nothing else no
  burrows, no urticated papules

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• Idiopathic Pruritus
• No identifiable cause found in up to 50 pts
• Can cause persistent and widespread itching and
  often extensive excoriation
• Common in 7th decade and beyond

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Management

• Treat any underlying cause
• Provide a patient information leaflet
• General measures
• Liberal emollients if at all dry keep in fridge
• Sedating antihistamines e.g. Hydroxyzine 25-50mg
  nocte /- 10mg tds through the day if required.
  Use periodically as tolerance may develop
• Topical agents e.g. 1 or 2 menthol in Aqueous
  cream, Eurax cream, Balneum Plus / Dermol
• Phototherapy may help in recalcitrant cases

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• Manage any features of anxiety or depression
• Consider low dose amitriptyline (25-75mg nocte)
• If associated with hepatic or renal disease or
  malignancy
• Can be difficult to treat
• Naltrexone and rifampicin have been reported as
  helpful in renal disease
• Cholestyramine can be effective if secondary to
  liver disease
• Avoid aggravating factors
• Reduce damage from scratching