Subcorneal pustular dermatosis

(Sneddon-Wilkinson Disease)

What are the aims of this leaflet?

This leaflet has been written to help you understand more about subcorneal pustular dermatosis and explains what this condition is, what it is caused by, how it can be treated and where you can find more information.

What is subcorneal pustular dermatosis?

Subcorneal (under the top layer of the skin) pustular (pus forming) dermatosis (skin problem) is a relatively harmless skin condition where you develop blisters at the skin surface. Women develop the condition more often than men (at a ratio of 4:1) and it usually starts after the age of forty, most commonly presenting between the fifth and seventh decades of life. It may come and go, and can eventually resolve, not requiring any further treatment.

Doctors Ian Sneddon and Darrell Wilkinson first described the condition in 1956, which is why it is also called Sneddon-Wilkinson disease.

What causes subcorneal pustular dermatosis?

The cause of subcorneal pustular dermatosis is unknown. It is not caused by infection and is not contagious or cancerous. Most often it occurs on its own, but has been linked to a variety of other diseases, for example inflammatory bowel disease, arthritis, thyroid disease and blood disorders.

Is subcorneal pustular dermatosis hereditary?

No, subcorneal pustular dermatosis does not run in families.

What are the symptoms of subcorneal pustular dermatosis?

Subcorneal pustular dermatosis presents suddenly and can be itchy or sore, but often does not cause any discomfort at all. Affected patients are usually well, and any other symptoms may prompt examination and investigation for
an underlying disease.

What does subcorneal pustular dermatosis look like?

It is a blistering skin condition with blisters developing on areas of normal looking skin or red and inflamed skin. Any area of skin can be involved, but the skin folds under the breast, underarm and the groin are common areas of
involvement. It is less common for forearms and lower legs to be affected.

The blisters develop quickly i.e. within hours and may be single or in clusters. The classical appearance of the blisters is that of a ‘half and half blister’ where the bottom half contains non-infectious pus and the top half contains clear
fluid. The top of the blister comes off easily, and then a scab forms. When the skin heals, it is often slightly darker than before, but this will very gradually fade over weeks or months, and scarring does not usually occur.

How is subcorneal pustular dermatosis diagnosed?

Sometimes the diagnosis is made just by looking at the skin, particularly in cases where there are the classical ‘half and half blisters’. A diagnosis is not always easy, as other blistering conditions, reactions to medicines and a form
of psoriasis (pustular psoriasis) can look very similar.

To confirm the diagnosis a small skin biopsy sometimes needs to be taken under a local anesthetic and then viewed under a microscope (histology).

Skin swabs or scrapings may also be taken to rule out a skin infection, and blood tests to look for an underlying illness

Can subcorneal pustular dermatosis be cured?

Presently there is no cure, but subcorneal pustular dermatosis can usually be controlled with medication.

How can subcorneal pustular dermatosis be treated?

Subcorneal pustular dermatosis usually clears over a period of about 4 weeks when treated with a tablet medication called dapsone (see Dapsone leaflet). The blisters can re-occur on stopping treatment therefore, intermittent
treatment for months or even years with a low dose of dapsone is often required to keep the skin clear. Steroid creams or steroid tablets can also be used with dapsone.

Alternative tablet medications are sulphapyridine and sulphamethoxypryidazine. Other treatments, for example acitretin, colchicine, tetracycline antibiotics, immunosuppressive medication or biological treatments can also be used successfully. Some patients respond to hospital treatment with ultra-violet light therapy.

The potential side effects of these treatments needs to be carefully balanced against the impact of subcorneal pustular dermatosis, which is a relatively harmless condition.

Where can I get more information about subcorneal pustular dermatosis?

Web links to detailed leaflets:

dermnetnz.org/scaly/subcorneal-pustulosis.html
www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=48377

For details of source materials used please contact the Clinical Standards Unit (clinicalstandards@bad.org.uk).

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel

BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED JANUARY 2014
UPDATED JANUARY 2017, JANUARY 2021
REVIEW DATE JANUARY 2024

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