1. Essential Dermatology for GPs
The Itchy Patient
Lucy Scriven

3. 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

4. What’s this?
Pompholyx

5. PLE

6. Bullous pemphigoid

7. Eczema

8. Lichen planus

9. Psoriasis

10. Scabies

11. Papular urticaria

12. 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

13. 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

14. 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

15. 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.

16. 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

17. 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

18. Asteototic eczema

19. Excoriations

20. ‘Butterfly’ distribution

21. Lichen simplex chronicus

22. Dermographic urticaria
Should be reproducible

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

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

25. 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

26. 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

27. 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

28. 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