Pruritus, generalised

Probability diagnosis

Psychological/emotional

Old, dry skin (senile pruritus)

Atopic dermatitis (eczema)

Contact (allergic) dermatitis

Varicella (chicken pox)

Serious disorders not to be missed

Cancer:

• lymphoma/Hodgkin

• leukaemia: CLL

• multiple myeloma

• other cancer, e.g. mycosis fungoides

Scabies (severe infestation)

Chronic kidney failure

Primary biliary cirrhosis/other causes (e.g. jaundice)

Pitfalls (often missed)

Pregnancy

Tropical infection/infestation

Polycythaemia rubra vera

Polyarteritis nodosa

Lichen planus

Generalised sensitivity (e.g. fibreglass, bubble bath)

Masquerades checklist

Depression

Diabetes

Drugs (several types; see list)

Anaemia (iron deficiency)

Thyroid (hyper and hypo) disorders

Spinal dysfunction (nostalgia paraesthetica)

Is the patient trying to tell me something?

Quite likely: consider anxiety, parasitophobia.

Key history

Enquire about nature and distribution of itching. Consider pregnancy, liver disease and malignancy of the lymphatic system, particularly Hodgkin lymphoma. A careful review of any drug history is important. Note any associated general symptoms such as fever.

Key examination

• General examination of the skin, abdomen and lymphopoietic systems

Key investigations

Consider:

• FBE/ESR/CRP

• urinalysis

• pregnancy test

• iron studies

• kidney function tests

• TFTs

• blood sugar

• chest X-ray

• skin biopsy

• stool examination (for ova and cysts)

• lymph node biopsy (if present)

• skin testing.

Diagnostic tips

• The itching of polycythaemia may be triggered by a hot bath and lasts for at least 1 hour.

• Pruritus can be the presenting symptom of primary biliary cirrhosis and may precede other symptoms by 1–2 years.

• The itch of Hodgkin lymphoma (in 30%) may be unbearable.

• Drugs that can cause pruritus: aspirin, barbiturates, morphine, cocaine, penicillin, other antibiotics, anticytotoxics.