Pompholyx (Dyshidrotic Eczema)

Synonyms: dyshidrotic eczema, cheiropompholyx or cheiropompholyx, and dyshidrotic dermatitis: (this implies that the condition is related to sweat glands, but this association is unproven).

The name pompholyx comes from the Greek word for bubble.

This is a dermatitis or eczema of unknown aetiology characterised by an itchy vesicular eruption of the hands, fingers and soles of the feet. It can be acute, recurrent or chronic and is difficult to treat effectively. It accounts of around 5% of cases of eczema of the hand. The usual age of those affected is 20 to 40 but it does affect teenagers and older people. There is a female preponderance of 2:1.

The term dyshidrosis indicates a sweating abnormality but histology reveals no evidence of eccrine glandular involvement. Histologically, the vesicles are intraepidermal with little or no inflammatory change.

Although the aetiology is unknown there are a number of commonly identified aggravating factors such as emotional stress. Allergic contact dermatitis may be involved, especially in recurrent cases.¹ Allergens such as chromate, neomycin, quinolones, or nickel have been implicated. There is an association with atopy and tenia pedis but both pompholyx and tinea pedis are likely to occur with sweaty feet and causation is not proved. Genetic factors are suspected in some families but no gene or gene locus has been identified.

The condition may be acute, chronic or recurrent.

• The affected areas are the centre of the palms or soles.
• It is usually symmetrical.
• After several hours of itching or burning in the hands, feet or both, the eruption develops. Tiny vesicles, about 1 or 2mm in diameter, erupt first along the lateral aspects of the fingers and then on the palms or soles.
• Palms and soles may be red and wet with perspiration.
• Later in the course there may be unroofed vesicles with inflamed bases, possibly accompanied by peeling or rings of scale or lichenification.
• Transverse furrows can develop on the nail when eruptions occur in the periungual area or nail matrix.
• Vesicle may break out in waves.
• The vesicles usually persist for 3 or 4 weeks and disappear spontaneously.

• Pustular psoriasis
• Fungal infection
• Recurrent focal palmar peeling (or keratolysis exfoliative)
• Dyshidrosiform bullous pemphigoid

There are no specific investigations that are indicated.

The condition is self limiting but as it can be intensely itchy, symptomatic treatment may be in order.

• Aluminum subacetate, or Burrow's Solution, is a drying soak that can be used if the lesions ooze.
• Large blisters can be drained under aseptic conditions.
• Antibiotics are only required if secondary infection occurs.
• Strong topical steroids to control itching and cold compresses are the usual first line treatment. From a practical point of view strong topical steroids work in the "active" phase - as the blisters are developing, Once they have dried skin emollients with occlusion (such as plastic gloves over night) may be useful prevent cracking of the skin.
• Second line treatment may be oral steroids.
• Long wave PUVA has been used.²
• Severe cases may be treated with oral methotrexate³ but this is rarely justified.
• Aluminum chloride 20% may help to control sweating.
• A developing treatment is intradermal injection of botulinum toxin.⁴

Secondary bacterial infection may occur. Emotional stress may have aggravated the disease and now the disease aggravates the stress.

Most patients recover spontaneously in 3 to 4 weeks but some have a chronic and unremitting course.