Hydroa vacciniforme

Hydroa vacciniforme is a rare, UV-induced, intermittent, bullous, scarring eruption of some or all of the exposed skin, typically occuring in children with a mean age of onset of 7.9 years.

This chapter is set out as follows:

• Unknown 

• Patients typically present with seasonal symptoms in spring / summer

• Following exposure to direct or window glass‐transmitted light, intensely itchy crops of papules and vesicles, often arising on a background of erythema and oedema, occur on exposed sites within 12–24 hours. A burning sensation and pain may occur

• There may be systemic malaise and fever during acute episodes

Distribution

• Lesions arise symmetrically, predominantly on the face, hands or forearms, and back of hands

Morphology

• Papules and vesicles
• As the vesicles resolve, haemorrhagic crusting develops and as this detaches, chickenpox-like scarring remains, which can be severe 

Other features

• There may rarely be cartilage destruction of the ears or nose
• Contractures of the digits
• The eyes can also be affected, with photophobia, conjunctivitis, keratitis, anterior uveitis, scarring and visual impairment
• Oral mucosal involvement is rare but can occur

• The differential includes porphyria and lupus so FBC, ANA, ENA and porphyrin screening are required

• Phototesting is usually undertaken 

• Provide a patient information leaflet on UV protection, window film is also required 

• Topical steroids

• Management in Secondary Care - oral steroids, β‐carotene, azathioprine, ciclosporin and antimalarials have all been tried, although their benefits are unproven 

• The condition is difficult to manage but often resolves in adolescence