Pruritus

Itching is part of many dermatological conditions

All patients with itchy rashes should be considered as possibly having scabies.

1. History of others itching.

2. Look between the fingers, around the wrists and ankles and the feet for burrows.

3. Check the nipples or penis and scrotum for nodules – these are almost diagnostic of scabies.

There is a fuller discussion in the Patient Information Pages.

Itching is usually accompanied by a rash eg eczema, psoriasis (sometimes), lichen planus, urticaria, dermatitis herpetiformis, nodular prurigo

In itchy patients without a rash, think of the following: -

1. Many elderly people itch and often have a dry skin. Moisturisers will often help.

2. Iron deficiency anaemia (check full blood count and serum ferritin). Try to elevate the ferritin level to 70 (i.e. mid range).

3. Thyroid disease (both over and under active). Check serum thyroxine and TSH.

4. Renal disease (check serum creatinine).

5. Liver disease (check LFTs) and hypercalcaemia.

6. Myeloproliferative disorders, eg, polycythaemia rubra vera (check full blood count and ESR).

7. Lymphoma, eg, Hodgkins and Non Hodgkins. Full examination and chest film.

8. Always check drug history. many drugs cause itching but the main culprits are opiate based drugs, ace inhibitors and statins

The younger the patient, the more suspicious of systemic disease one should be, especially of lymphoma.