2. بسم الله الرحمن الرحيم

3. PRURITUS
د. رزان

4. Objectives: 1. to define pruritus. 2. to classify its causes.

5. PRURITUS
Definition: PRURITUS : Itching= Unpleasant sensation that provokes the desire for scratching. Scratching: Is the action taken in response to itching. Itching= sensation. Scratching=action.

6. P. is the commonest dermatologic complaint.
It is not a diagnosis.
P. is a symptom that may be caused by many conditions.

8. Itch pathway Mediatedors: mainly ;histamine from mast cell.
other mediatedors: vasoactive chemicals like serotonin, bradykinin.
Itch nerve ending are lie very close to dermo-epidermal junction.
Itching sensation is transmitted via C fibers(slow conduction speed) through spino-thalamic tract to the thalamus & on to a cortical representation

9. How to analyze itching? Site Duration Onset Diurnal variation.
Severity.
Precipitating factors.
Aggravating factors.
Alleviating factors.
Associated features.

10. *Classification: Itchin g Localized Acute Chronich. Generalized

11. Generalized Pruritus:-
Acute Generalized pruritus:
Wide spread urticaria.
Scabies.
Acute allergic contact dermatitis.
Drug eruption.
Pediculosis corporis.
Acute erupted lichen planus.

12. pure cutaneous disease
Chronich-Generalized itching
pure cutaneous disease
systemic cause

13. A) Pure cutaneous causes of chronich generalized itching;
Atopic dermatitis.
Seborhoic dermatitis.
Senile pruritus.
Dry skin.
Dermatitis herpitiformis.
Cutaneous T cell lymphoma(Mycosis fungoides).

14. B) Systemic causes: Neuro-psychogenic pruritus. Endocrine disease;
a-Hyper thyroidism & Hypothyroidism;
b-D.M.
c-Pregnancy; (Obstetric Cholestasis.).
Liver disease; a- Cholestatic jaundice; b-Primary Biliary Cirrhosis. c-Chronic active hepatitis(HBV & HCV).
Renal disease; -Chronic renal failure;
Blood disease; a-Polycythaemia rubra vera.
b-Iron deficiency anaemia; c-Leukaemia; lymphoma, Myeloma.
6. Malignancy;
a-Hodgkin's disease;
b-Carcinoma; Ca. breast, bronchus, stomach & pancreas.
7. HIV .

15. Localized chronic itching:
Lichen planus.
Chronic contact dermatitis.
Nurodermatitis
Pomphylax
Discoid eczema
Varicose dermatitis.
Asteatotic eczema.
Lichen sclerosus it atrophicus.
Paget disease.

16. Localized –acute itching:
Insect bite
Acute contact dermatitis.
Photodermatitis
Fixed drug eruption.
Pediculosis pubis& capitis.
Worm infestation (Oxyuriasis).

17. Diagnosis: Mainly clinical Simple Investigations.
Sophisticated Investigations.
According to the suspected cause.

18. Treatment: A-General measures: Reassure. Explain the condition.
Treat the primary underlying cause.
Avoid aggravating factors(scratching).
Gentle skin care.

19. B-Topical measures: Topical Emollients agent on skin.
Topical antihistamine.
Topical CS (have potent anti-pruritic effect).
Tacrolimus and pimecrolimus.
Other therapies to decrease itching include:
Topical menthol 1%, camphor.

20. C-Systemic therapies
Systemic H1 blocking anti histamines (either sedative or not).
-Systemic CS (short course small dose).
D-Others:
Phototherapy: UVB & PUVA.

21. Thank you