Hydroa vacciniforme

Published on 19/03/2015 by admin

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Last modified 19/03/2015

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Hydroa vacciniforme

Herbert Hönigsmann

Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports

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Hydroa vacciniforme (HV) is a very rare, idiopathic photodermatosis that mainly starts in childhood, frequently resolving by adolescence or young adulthood. Its prevalence is 0.1–0.5 cases per 100 000 per year. It is characterized by recurrent crops of papulovesicles or vesicles, most commonly on the face and the dorsa of the hands, but other sun-exposed areas of the skin, such as the lower lips, may also be involved. The vesicles resolve with pock-like scarring. The disease was first described by Bazin in 1862, and it is possible that before the clear definition of erythropoietic protoporphyria by Magnus et al. in 1961, some cases may have been protoporphyria rather than hydroa because of the similarity of symptoms. There are now a number of reports of an association with Epstein–Barr virus (EBV) infection mainly from Japan and China, but not all these cases are typical: they are associated with NK/T-cell lymphoproliferative disorders with a frequently fatal outcome. Recently such cases were also reported from South America. EBV DNA blood load was strongly positive in the seven French adult patients with HV. A Swedish study in four children with EBV-associated HV treated with acyclovir/valacyclovir showed a good clinical response.

Management strategy

Hydroa vacciniforme usually presents in childhood, sometimes with spontaneous improvement during adolescence. Parents generally seek specialist advice because their children are unable to tolerate sunshine (play outdoors or travel abroad) and because the eruption can result in considerable scarring, both of which cause significant morbidity.

Hydroa vacciniforme is almost always refractory to any treatment, but restriction of sun exposure, appropriate clothing, and regular use of broad-spectrum sunscreens with an effective UVA filter can help in mild to moderate disease. Windows in the car and home can be covered with films that filter UV wavelengths less than 380 nm.

In patients with more severe disease, however, courses of narrowband UVB phototherapy or psoralen with UVA (PUVA) administered as for polymorphic light eruption may help occasionally. Both phototherapy regimens usually consist of thrice-weekly treatments for an average of 3 to 4 weeks. It is important to administer these therapies carefully to avoid provoking disease exacerbations.

Antimicrobial therapy has also been tried, as have antimalarials and systemic immunosuppressive therapy, including intermittent oral corticosteroids, but although occasionally helpful, none of these appear to be reliably effective. β-Carotene, used in several studies, however, was mostly shown to be ineffective.

For severe and refractory HV unresponsive to other therapies, immunosuppressive agents including azathioprine and cyclosporine may be effective, but thalidomide does not seem to be. However, the use of immunosuppressive drugs for an admittedly unpleasant, but otherwise benign, disease should be carefully considered.

In two reports, dietary fish oil rich in omega-3 polyunsaturated fatty acids was associated with clinical improvement in three of four patients. The mechanism may be through inhibition of prostanoid production and by their proposed buffering effect against free radical-induced damage.

The rare nature of this condition means that there are no large or randomized trials. Evidence for treatment is based on case series or single reports.

Specific investigations

Photoprovocation testing induces typical blisters. Light tests are abnormal in the UVA range. Photographs to the right of the figure show the result of photoprovocation with UVA (three times 30 J/cm2 on 3 consecutive days): (A) after 24 hours; (B) after 48 hours; and (C) after 2 weeks.

Serology for antinuclear antibody and extractable nuclear antigens (anti-Ro, La, and Sm) will exclude bullous lupus erythematosus, which quite commonly can be ruled out by its clinical symptoms.

Rare cases have been associated with metabolic disorders, such as Hartnup disease, and so aminoaciduria should be ruled out.

Screening for EBV should be done in view of the increasing number of reports of the possible association.