Excerpt from Dyshidrotic Eczema

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Background

Dyshidrotic eczema is a type of eczema (dermatitis) of unknown cause that is characterized by a pruritic vesicular eruption on the fingers, palms, and soles. The condition affects teenagers and adults and may be acute, recurrent, or chronic. A more appropriate term for this vesicular eruption is pompholyx, which means bubble. The clinical course of dyshidrotic eczema can range from self-limited to chronic, severe, or debilitating. The condition's unresponsiveness to treatment can be frustrating for the patient and physician.

The definition and causes of dyshidrotic eczema remain enigmatic.¹ A lack of precision in definition has rendered accurate analysis of causation and comparisons of therapeutic strategies challenging. Some believe the terms pompholyx and dyshidrosis are obsolete and favor a new term, such as "acute and recurrent vesicular hand dermatitis."

Pathophysiology

The etiology of dyshidrotic eczema is unknown. The condition was inaccurately described in 1873 as dyshidrosis because of the clinical symptom of sweaty palms. The term dyshidrosis indicates a sweating abnormality, although histologic examination reveals no evidence of eccrine glandular involvement. Histologically, the vesicles are intraepidermal and spongiotic with little to no inflammatory changes. The more appropriate term for this vesicular eruption is pompholyx, which means bubble. Although strong reasons to use the term pompholyx have been noted, dyshidrotic eczema remains a commonly used term. A tiny percentage of individuals with the disorder note flares after ingesting metal salts, specifically chromium, cobalt, and nickel. Diets that eliminate these metal salts may rarely have some clinical benefit.

One causative study observed reactional pompholyx to interdigital-plantar intertrigos and endogenous reactions to metals or other allergens; however, an unexpected number of patients with so-called contact pompholyx, in which cosmetic and hygiene products play a preponderant role (compared with metals), were also reported.²

A genetic component to the development of dyshidrotic eczema may be involved in some patients. Dyshidrotic eczema has been described in few large families; no gene or locus had been identified.³ A genome-wide search in a large Chinese family identified a locus at chromosome 18q22.1-18q22.3, with a maximum 2-point logarithm of the odds (LOD) score of 3.61 at marker D18S1131 (theta = 0.00). Haplotype analyses showed the gene to be located within 12.07 cM region between markers D18S465 and D18S1362, which corresponds to 8 Mb.

Frequency

United States

Dyshidrotic eczema accounts for 5% of all cases of eczema of the hand.

Mortality/Morbidity

Dyshidrotic eczema has no associated mortality, although some severe cases can become debilitating.

Race

No racial predilection is reported.

Sex

The female-to-male ratio is 2:1.

Age

Peak incidence occurs in patients aged 20-40 years, although the disorder also occurs in teenagers and older patients.

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