Pruritus

May occur with or without an underlying skin disease.

Xerosis/dry skin is one of the commonest causes of itch especially in elderly patients.

In the absence of overt skin disease consider the following :

Itch associated with underlying medical conditions:

Medication related itch:

In particular morphine and other opioids, statins, ACEI, NSAIDs, digoxin, antimalarials and sulphonamides

Neurological itch:

Brachioradial pruritus – itch localised to dorsi-lateral forearm (sometimes shoulder).
Notalgia paraesthetica – itch localised to between or below the scapulae.

Psychogenic itch:

Infections/infestations (skin changes not always obvious)

Idiopathic itch:

Consider the following diagnoses:

Candidiasis
Dermatophyte infection
Irritant dermatitis or allergic contact dermatitis
Lichen simplex
Lichen sclerosus
Infestation with thread worms
Intra-epithelial neoplasia — ask about previous history of anogenital warts or cervical intra-epithelial neoplasm

Treat any underlying disease
Frequent & plentiful use of emollient and soap substitutes (see Eczema pages for more details). Consider if relatives/carers needed to apply in elderly patients.
Crotamiton cream can be helpful in soothing itch after scabies and calamine after chicken pox.
Oral antihistamines (sedating type may be more helpful in itch especially at night, though non-sedating may be safer in the elderly)
Consider menthol in aqueous cream (0.5%- 2%). Dermacool (1% menthol in aqueous cream) is listed on the Lothian Joint Formulary. It is not licensed as a medicine, but it is reimbursable on GP prescriptions as it is listed in part 7U of the drug tariff
5% doxepin hydrochloride cream can be helpful for localised areas of itch though is non-formulary.
If medication is suspected, discontinue for a few weeks (if possible) and see if symptoms improve.

Investigations as appropriate