By Gary M. White, MD
Hidradenitis suppurativa (HS) is a chronic, inflammatory condition of the flexural areas. Although the initial lesions appear infectious--like abscesses--they are not. Secondary infection of ruptured lesions and sinus tracts are common, however. In one study of axillary lesions [J Med Microbiol 1999;48;103], Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa were typical aerobic bacteria. A variety of anaerobic organisms were found as well. Indeed, a polymicrobial picture is often seen and culture and therapy should reflect this. HS may be part of the follicular occlusion triad along with dissecting cellulitis of the scalp and acne conglobata. See also HS in children.
The patient is usually a woman with inflammatory nodules of the axilla and/or groin that may rupture, drain, and cause scarring. Some patients have more comedonal disease, others inflammatory nodules, and others erosive lesions. Onset is generally after puberty and most common between 20-24 years of age. The perianal and inframammary areas are commonly affected as well. Sinuses, fistulas, and scars accumulate over time. Lesions are often quite painful or sore. Primary lesions are sterile but staphylococcal or other bacteria commonly infect secondarily. Rarely, a squamous cell carcinoma may develop in the setting of chronic HS. Chronic anemia may be associated and can cause chronic fatigue [JEADV 2016;230;174].
One group separated HS into 3 phenotypes [JID 2013;133]:
Patients with HS, and particularly women, experience great distress in their sex life. Embarrassment, frustration, and sadness are common. Asking a simple question about sexual satisfaction allows the patient, if she desires, to open up and express these feelings and may lead to better treatment approaches [JAAD Sept 2012].
Metabolic syndrome (MeS) combines obesity, dyslipidemia, hyperglycemia, and hypertension and is correlated with an increased risk for the development of cardiovascular disease. In one study of HS [JAAD April 2014], the prevalence of MeS was 50%.
Onset before puberty is uncommon, but does correlate with a greater severity later in life and a positive family history [JAAD 2015;72;485].
Potential complications include keloid scars, fistulas, lymphedema, SCC, anemia of chronic disease, amyloid of the skin and/or kidney with the development of nephrotic syndrome, scarring, and limb contractures.
Friction and moisture in the affected areas should be reduced as much as possible. Weight loss can greatly improve the condition if the patient is overweight [Acta Derm Vener 2014;94;553]. Topical clindamycin may be helpful (or benzoyl peroxide 10% wash). Bleach baths and Hibiclens may have some benefit. Smokers should stop. Tell the patient the condition is not contagious and is not caused by poor hygiene. Bacterial cultures may occasionally be done to rule out other causes or secondary infection.
Treatment of inflammatory nodules early (e.g., within several days) with intralesional steroids (e.g., TMC 5-10 mg/cc) can give the patient great relief. In one study utilizing triamcinolone 10 mg/cc [JAAD 2016;75;1151], pain was reduced after 1 day and signs of inflammation after 7 days.
Oral antibiotics can be very helpful. Several experts recommend treatment with the combination of clindamycin 300 mg and rifampicin 300 mg both BID for 10 weeks. On the plus side, rifampicin acts against Clostridium difficule infections, decreasing the risk of colitis. On the down side, rifampicin can inactivate BCPs. Also, it can turn bodily secretions orange, e.g. tears, sweat and urine.
Other options include amoxicillin with clavulanic acid or fluoroquinolones (e.g., ciprofloxacin). Trimethoprim with sulfamethoxazole may also be beneficial. One study showed Staphylococcus epidermidis, Proteus mirabilis, and Staphylococcus aureus to be the most common isolates [Acta Derm Venereol 2014; 94: 699–702].
Dapsone, 5-200 mg/day, may be helpful.
For axillary involvement, laser hair removal can be quite helpful.
If oral and topical antibiotics plus general measures are not sufficient, a biologic agent is often added. Adalimumab is FDA-approved for moderate to severe HS that is resistant to conventional therapies. In one RDBPCT, adalimumab weekly was superior to both adalimumab every other week and placebo [J Drugs Dermatol 2016;15;1192].
Metformin [JEADV 2012;27;1101] and more recently liragutide [Br J Dermatol 2017;177;858] have shown benefit in difficult to control HS. In overweight or obese patients with recalcitrant disease, these agents may be beneficial.
In comparing all the biologic agents, one review put the percent responders at 89% infliximab, 79% adalimumab, and 56% for etanercept [BJD 2013;168;243-52]. Ustekinumab has also been used in a few patients. Infliximab seems to be most effective but in one study 22% experienced serious adverse events, the most common being infusion reactions, and one patient died of pneumococcal sepsis. In one study [BJD April 2014] of 11 patients with severe HS unresponsive to more than three prior therapies, infliximab 5 mg/kg every four weeks was given. Nine of the 11 patients remain well-controlled on this regimen.
Canakinumab is a human IgGk monoclonal antibody targeting IL-1B. It was beneficial in two patients with severe HSA [JAMA Derm 2017;153;1195].
In a small study of 9 patients with HS treated with apremilast, 6 were able to finish the study and of those, 5 showed a promising response [JAAD 2017;76;1189].
Acitretin in one study of 12 patients did incredibly well [BJD Jan 2011]. The average dose was 0.67 mg/kg/day. Nine patients achieved marked or complete remission after one course. The improvement generally started within two months and further improvement was achieved within the first six months of therapy. Isotretinoin has not shown analogous results.
A few case reports highlight the benefit of cyclosporin. One patient did well on long-term cyclosporin 5 mg/kg/day, then 3 mg/kg/day [JAAD Dec 2012].
In one report [JAAD 2016;75;1061], 13 patients were treated initially with prednisone 10 mg/day (ultimate dose varied from 5-15 mg/day). This was given in addition to existing therapy when that was not sufficient for control (e.g., acitretin, adalimumab, dapsone, clindamycin, doxycycline). All patients received calcium (1200 mg/day) and vitamin D (1000 IU/day) and monthly glucose monitoring. Overall, 11/13 patients showed a clinical response with the addition of low-dose prednisone. Side effects were minor and included hyperglycemia, sleep disturbance, and mild psychomotor agitation.
Some women experience a premenstrual flare. For them, antiandrogen therapy (e.g., spironolactone) may be helpful.
Finasteride has been used in children with HS with success [JAMA Derm 2013;149(6):732-35 and PD 2017;34;578]. Three female patients, ages six, seven, and 15 who had failed standard therapy including isotretinoin, were treated with finasteride 1.25-10 mg/day for up to six years. Adjunctive BCPs were given if the patient was a menstruating female. Treatment resulted in decreased frequency and severity of disease flares with no significant adverse effects.
Anakinra (IL-1 receptor antagonist) showed benefit in a study of five patients [J Am Acad Dermatol. 2014;70:243-51]. Another study randomized 20 patients to receive either anakinra or placebo for 12 weeks. The disease activity score was decreased at the end of treatment in 20% (2 of 10) of the placebo arm compared with 67% (6 of 9) of the anakinra arm [JAMA Derm 2016;152;52]
If after 3–6 months sinuses and fistulas are not responding to treatment, they may be removed surgically [BJD July 2012]. Incision and drainage are usually not helpful as lesions invariably recur. Instead deroofing an inflammatory nodule, curetting the base, and letting it heal by secondary intention is recommended. Eventually, if medical therapy is not successful and the patient desires a "cure," a surgical approach may be considered. This usually consists of excision of all diseased tissue in the area. Limited excisions usually result in recurrence adjacent to the scar. In one study, limited excision of diseased tissue had a 43% recurrence rate whereas radical excision had only a 27% recurrence rate [Int J Colorectal Dis 1998;13;164].
See HS in children.
Dapsone was not very effective in a series of 24 patients. In one study [JAAD 1999;40;73], monotherapy with isotretinoin had limited benefit.
HS of the buttocks and groin. As always, the inflammatory component is harder to see in darker-skinned patients. This is an example of the type 3 phenotype as noted above.
Hidradenitis suppurativa of the groin and axilla in a woman.
The left axilla of a young, obese woman who smokes.
This patient has bridged comedones and dilated pores of the axilla, with a phenotype that overlaps with acne conglobata.
Squamous cell carcinoma developing in chronic HS. Dermatology Online Journal 21(4)
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