Vasculitis is a recognised but unusual complication of CF occurring in approximately 2–3% of patients.2 6–10
The majority of cases in the current literature, which mainly comprises of case reports and case series, occur in patients over 20 years of age.2
The case we have presented is classic in that of the age group (over 20), the distribution of the rash (distal lower limbs) and the prognosis (often poor). Diagnosis is usually made clinically, however, if a skin biopsy is performed, histology will show features consistent with leukocystoclastic vasculitis.6
The underlying aetiology of CF-related vasculitis is not known. A multifactorial cause has been suggested, involving associations with bacterial antigens, hypergammaglobulinaemia, immune complexes and drug therapy.5
While it has been reported that there is no clear association between infective exacerbations or sputum microbiology and vasculitis,1
it has also been postulated that autoantibodies against bactericidal/permeability-increasing protein antibodies (BPI) might play a role.2
These are found frequently in patients with CF with vasculitis and levels appear to correlate with pseudomonal load, reduction in lung function and the presence of vascultis.2 10
BPI expresses a protective activity against lipopolysaccharide-induced injury on vascular endothelial cells.2 11
Thus, if anti-BPI antibodies interfere with this function, it is thought they may facilitate vasculitic inflammation.2
A significant proportion of patients with CF-related vasculitis also report arthralgia, and systemic involvement is possible. In the latter, urgent treatment is required with steroids and immunosuppressive drugs.5
- Vasculitis in CF is usually cutaneous.
- CF-related vasculitis is associated with more advanced disease1 and a poor prognosis.2
- Complete and thorough investigation is essential for early detection of systemic vasculitis and at regular intervals during the course of an unremitting rash.