Hidradenitis suppurativa (HS) - technical article
This is a chronic, inflammatory, suppurative disease affecting apocrine-gland bearing skin sites, including the axillae, groins, perineum and/or submammary area (in women). Occlusion of the follicular infundibula is the initial event in pathogenesis.
This is followed by inflammation of the apocrine glands and rupture of the follicles. Painful, inflamed nodules and sterile abscesses result in sinus tract formation, fistulae, and scarring. Distinction from septic furunculosis may be difficult in the early stages.
The aetiology of HS is unclear; it is more common in women than men and the incidence in England is 1:600. Patients of African descent have a higher incidence than Europeans. A familial form of HS with autosomal dominance has been described. Specific bacteria, e.g. anaerobic streptococci like Streptococcus milleri have been reported in HS and although cultures are frequently sterile, microbiological assessment allows treatment to be based on documented sensitivities.
However, treatment is notoriously difficult. Reducing friction and moist hot environments, together with weight reduction and cotton clothing will help some patients. Localized inflammatory lesions benefit from intralesional injections using triamcinolone (5 mg/ml). Small studies have shown a combination of oral clindamycin (300 mg twice daily) and rimfampicin (600 mg daily) is also beneficial.
Systemic antibiotics, including erythromycin 500 mg twice each day or minocycline 100 mg daily, are frequently used but topical clindamycin lotion is the only antibiotic that has been shown to be beneficial in a double-blind, placebo-controlled trial.
Systemic steroids frequently produce dramatic improvement but recurrence is usual on withdrawal. Antiandrogen therapy alone as cyproterone acetate or in combination with ethinylestradiol has been used successfully in women. Isotretinoin produces minimal benefit and the longer acting retinoid acitretin 25 mg daily has shown more promise.
Ciclosporin A and the tumour necrosis factor-α (TNFα) inhibitor infliximab have demonstrated improvement in refractory disease. Good results have been reported following radical surgical excision of involved areas with laying open of sinus tracts.