Hidradenitis suppurativa (HS), also known as acne inversa, is an inflammatory occlusive disorder affecting the follicles of the folliculopilosebaceous units (FPSUs) in intertriginous areas.1,2 The typical initial manifestation of HS involves 1 or more inflamed nodules in an intertriginous area,1 with the axillae and genitofemoral folds affected most frequently.3 Nodules are erythematous and painful, ranging from 4 to 10 out of 10 when rated by patients on a numerical rating scale,4 and may regress after 1 week to several weeks.3,4 Nodules also may progress to form abscesses that drain unprovoked, producing purulent or blood-tinged discharge that causes significant distress because of odor and location, and may require wound dressings.4 Lesions may recur in the same site or in intertriginous areas.3
Sinus tracts, also known as skin tunnels, may form with recurrent nodules and can produce malodorous purulent drainage.3 Scarring manifests late in the disease course, and occurrence in the axillae may result in thick bands that restrict range of motion in the shoulder. Sinus tracts, “tombstone” comedones, and scarring develop in very severe cases,3 with these structures indicative of recurrent disease and end-stage damage to the FPSUs. Treatment of HS early in the disease course is crucial to prevent progression to these more severe manifestations.1,5
Measuring Severity of Hidradenitis Suppurativa
The severity of HS is most frequently assessed using the Hurley staging system (Table).1 Hurley stage I is the most common stage of HS.1,6
Table. Staging of Hidradenitis Suppurativa1
|I||1 or more nodules or abscesses form without sinus tracts or scarring; this is the most common stage of HS|
|II||Recurring lesions separated by normal skin, sinus tracts, and/or scarring in 1 or more intertriginous areas|
|III||Diffuse lesions with interconnecting sinus tracts, without normal skin intervening|
Source: Goldburg et al.1
The onset of HS typically occurs in early adolescence.1 A delay in the recognition of HS results in many patients being diagnosed, on average, 7 years after the appearance of symptoms and a mean diagnosis in the third decade of life.1,6 A meta-regression analysis of 16 studies conducted primarily in Western countries found the prevalence of HS in the general population to be 0.4%, similar to that of other inflammatory disorders, such as rheumatoid arthritis.2 However, the prevalence of HS varies considerably based on estimation method, ranging from 0.05% to 4.1%.7 Women are twice as likely as men to be diagnosed with HS, and HS is 3 times more prevalent among Black compared with White Americans.7 Involvement of the perineal and perianal areas is more common in men, whereas women are more likely to have HS lesions in the axillary, inframammary, and genitofemoral areas.8
Patients with HS have high rates of comorbidities such as obesity, metabolic syndrome, diabetes mellitus, tobacco smoking, Crohn disease, and psychiatric disorders.9 Many comorbidities are inflammatory9 and dermatologic in nature; these include psoriasis and diseases belonging to the follicular occlusion triad (HS, acne conglobata, and dissecting cellulitis) and tetrad (triad diseases plus pilonidal cysts).1 As with all disorders of the follicular occlusion triad and tetrad, follicular occlusion combined with mechanical stress is hypothesized to play a role in the development of HS,10 with hyperkeratotic follicles, hyperplastic epithelium, and inflammation implicated as initial mechanisms in an examination of biopsy samples.10 In addition, an impaired Notch signaling pathway and abundant inflammatory markers — such as interleukin (IL)-1, IL-12, IL-23, and tumor necrosis factor (TNF)-α — have been reported in samples from patients with HS.11 Obesity and smoking are believed to stimulate the release of these inflammatory cytokines and amplify downregulation of the Notch signaling pathway, augmenting the pathophysiology of HS.11 Obesity may contribute to mechanical stress and follicular occlusion, accelerating the development of HS.11
Diagnosis of HS is clinical, with 3 generally agreed-upon criteria: characteristic inflammatory lesions, a tendency of lesions to occur in intertriginous or lax flexural areas, and recurrence of lesions.1 Early lesions are often misidentified as furuncles,8 contributing to the delay in accurate diagnosis.3 The appearance of lesions helps differentiate these diseases; furuncles have a pointed appearance, whereas HS nodules contain a rounded roof because of their location deeper in the subcutaneous tissue.8
Crohn disease should be included in the differential diagnosis of a patient presenting with an abscess or sinus tract in the perineal or perianal area. Crohn disease and HS share several pathophysiologic characteristics: epithelial involvement, genetic predisposition, smoking as a risk factor, fistula formation, and inflammatory markers such as TNF-α.12 Co-occurring cases of HS and Crohn disease have been reported.12
Management of Hidradenitis Suppurativa in Primary Care
Skin biopsies or wound cultures are unnecessary for the diagnosis of HS unless needed to exclude other disorders. Bacterial culture also is not required for diagnosis unless superinfection is suspected, as cultures of purulent discharge from HS nodules and abscesses are most commonly negative.8 Because of the high comorbidity burden among patients with HS, those presenting with a suspicious lesion and a history of obesity, diabetes mellitus, metabolic syndrome, or current tobacco smoking should be assessed for HS.5
Primary care providers can employ multiple tools to initiate the management of HS. Educating patients on the etiology of the disease is crucial. Patients may have misconceptions that HS results from poor hygiene or is somehow self-induced; it is important to dissuade patients from this misconception.
Individuals with HS experience higher rates of psychiatric disorders, drug and alcohol dependence, sexual dysfunction, and distress compared with the general population.5,13 They have higher rates of depression and anxiety, have more severe depression and anxiety, and are at greater risk for suicidal ideation and death by suicide.14 High rates of depression are seen with other chronic skin diseases, such as psoriasis, but the severity of depression is greater among patients with HS,14 reflecting the greater physical severity of the disease. Professional psychological support should be offered to all patients with HS.15
Additional education on pain management and wound care is recommended, as lesions are frequently painful and can become open wounds. Although the etiology of HS has not been definitively ascertained, clinical evidence demonstrates a reduction in HS severity and recurrence with smoking cessation and weight loss, likely because of a reduction in Notch pathway impairment, inflammation, and skin shearing.16,17
Choice of initial medication for HS management depends on severity as defined by the Hurley staging system. For Hurley stage I disease, topical clindamycin is the antibiotic of choice. For Hurley stage II and III disease, an oral antibiotic, most commonly a tetracycline such as doxycycline, is used. Oral clindamycin and rifampin should be prescribed if inflammation is significant, and combination therapy with oral metronidazole, moxifloxacin, and rifampin is used in refractory disease.18,19
Spironolactone and estrogen-containing combined oral contraceptives may be appropriate in women with HS, especially if they have comorbidities involving androgen excess, such as polycystic ovarian syndrome.19 Metformin may be used in patients with HS and insulin resistance or diabetes mellitus; it may promote weight loss, further benefiting patients with HS and obesity.18 Retinoids have been applied historically for HS,18 but isotretinoin is no longer recommended unless the patient has concomitant acne vulgaris because of the differences in pathophysiology of this disease and HS.1,10,18
As noted, acutely inflamed nodules produce significant pain in patients with HS.10,20 Along with warm compresses, intralesional corticosteroid injections may be beneficial.18,19 Intralesional triamcinolone reduces inflammation and pain but is not suitable for the prevention of HS flares.19 Medication selection ultimately depends on the patient’s individual disease course and clinical decision-making by the provider. The biologic agents adalimumab, bimekizumab, and secukinumab have been effective in the systemic treatment of HS.21
Surgical intervention is reserved primarily for Hurley stage II to III disease.22 Surgical interventions for HS include incision and drainage, punch debridement, unroofing, and wide excision.19,22 Incision and drainage is performed on acute, fluctuant nodules,22 but this technique can contribute to misdiagnosis as an uncomplicated abscess, leading to delay in proper treatment for HS.13 Incision and drainage does not decrease the recurrence of HS lesions because affected FPSUs remain in the skin.14 Punch debridement is also used to treat acute nodules and is superior to incision and drainage in reducing recurrence.15 If a patient presents with recurring lesions necessitating incision and drainage, further workup is needed to rule out a chronic inflammatory disorder such as HS.13,14
Importance of Early Recognition of Hidradenitis Suppurativa
Timely diagnosis of HS represents an unmet medical need, as patients are frequently diagnosed years after the onset of symptoms.3 As noted, HS causes emotional distress for affected patients.3 Radical surgery is the only curative option for HS, and despite its use, the disease may recur in a different anatomic region, necessitating continued medical management.23 Patients with HS are at a greater risk for developing squamous cell carcinoma because of impairment of the Notch signaling pathway, which increases the likelihood of malignant transformation.11,24
The issue of impaired quality of life in patients with HS is further amplified in people of color, as described in a review by Lee et al.25 People of color are more likely to develop obesity, insulin resistance, and metabolic syndrome than White people.25 People of color also have a greater prevalence of low socioeconomic status and reduced access to both primary and specialty health care.25 People of color experience higher rates of psychosocial stressors,25 and because Black Americans are diagnosed with HS at a much higher rate than White Americans,7 they may be at higher risk for developing new or worsening depression. Providers should evaluate their patients with HS — especially patients of color — for psychiatric diseases such as depression.
The management of HS should be individualized to the patient and provider. Because the initial presentation is variable, accurate diagnosis and prompt treatment may be difficult. Nonetheless, these are crucial to preventing progression to more severe stages, and providers should approach patients with recurrent intertriginous lesions with a high suspicion for HS. If primary care providers are able to close the 7-year average gap between symptom onset and a diagnosis of HS, patients can be adequately treated early in their disease course, avoiding the potentially disfiguring physical manifestations of the disease, reducing its psychosocial burden, and minimizing costly medical care.
Kirstin Shaffer, PA-C, is a graduate of the Physician Assistant program at Augusta University College of Allied Health Sciences, in Augusta, Georgia. Alicia Elam, PharmD, is an associate professor in the Physician Assistant Department at Augusta University College of Allied Health Sciences.
1. Goldburg SR, Strober BE, Payette MJ. Hidradenitis suppurativa: Epidemiology, clinical presentation, and pathogenesis. J Am Acad Dermatol. 2020;82(5):1045-1058.
2. Jfri A, Nassim D, O’Brien E, Gulliver W, Nikolakis G, Zouboulis CC. Prevalence of hidradenitis suppurativa: A systematic review and meta-regression analysis. JAMA Dermatol. 2021;157(8):924-931.
3. Jemec GBE. Clinical practice. Hidradenitis suppurativa. N Engl J Med. 2012;366(2):158-164.
4. Smith HS, Chao JD, Teitelbaum J. Painful hidradenitis suppurativa. Clin J Pain. 2010;26(5):435-444.
5. Kamp S, Fiehn AM, Stenderup K, et al. Hidradenitis suppurativa: a disease of the absent sebaceous gland? Sebaceous gland number and volume are significantly reduced in uninvolved hair follicles from patients with hidradenitis suppurativa. Br J Dermatol. 2011;164(5):1017-1022.
6. Saunte DM, Boer J, Stratigos A, et al. Diagnostic delay in hidradenitis suppurativa is a global problem. Br J Dermatol. 2015;173(6):1546-1549.
7. Garg A, Kirby JS, Lavian J, Lin G, Strunk A. Sex- and age-adjusted population analysis of prevalence estimates for hidradenitis suppurativa in the United States. JAMA Dermatol. 2017;153(8):760-764.
8. Vazquez BG, Alikhan A, Weaver AL, Wetter DA, Davis MD. Incidence of hidradenitis suppurativa and associated factors: a population-based study of Olmsted County, Minnesota. J Invest Dermatol. 2013;133(1):97-103.
9. Shlyankevich J, Chen AJ, Kim GE, Kimball AB. Hidradenitis suppurativa is a systemic disease with substantial comorbidity burden: a chart-verified case-control analysis. J Am Acad Dermatol. 2014;71(6):1144-1150.
10. von Laffert M, Stadie V, Wohlrab J, Marsch WC. Hidradenitis suppurativa/acne inversa: bilocated epithelial hyperplasia with very different sequelae. Br J Dermatol. 2011;164(2):367-371.
11. Melnik BC, Plewig G. Impaired Notch signalling: the unifying mechanism explaining the pathogenesis of hidradenitis suppurativa (acne inversa). Br J Dermatol. 2013;168(4):876-878.
12. van der Zee HH, van der Woude CJ, Florencia EF, Prens EP. Hidradenitis suppurativa and inflammatory bowel disease: are they associated? Results of a pilot study. Br J Dermatol. 2010;162(1):195-197.
13. Kurek A, Peters EM, Chanwangpong A, Sabat R, Sterry W, Schneider-Burrus S. Profound disturbances of sexual health in patients with acne inversa. J Am Acad Dermatol. 2012;67(3):422-428.e1.
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15. Esmann S, Jemec GB. Psychosocial impact of hidradenitis suppurativa: a qualitative study. Acta Derm Venereol. 2011;91(3):328-332.
16. Bukvić Mokos Z, Miše J, Balić A, Marinović B. Understanding the relationship between smoking and hidradenitis suppurativa. Acta Dermatovenerol Croat. 2020;28(1):9-13.
17. Garg A, Papagermanos V, Midura M, Strunk A. Incidence of hidradenitis suppurativa among tobacco smokers: a population-based retrospective analysis in the U.S.A. Br J Dermatol. 2018;178(3):709-714.
18. Alikhan A, Sayed C, Alavi A, et al. North American clinical management guidelines for hidradenitis suppurativa: a publication from the United States and Canadian Hidradenitis Suppurativa Foundations: Part II: topical, intralesional, and systemic medical management. J Am Acad Dermatol. 2019;81(1):91-101.
19. Nazary M, van der Zee HH, Prens EP, Folkerts G, Boer J. Pathogenesis and pharmacotherapy of hidradenitis suppurativa. Eur J Pharmacol. 2011;672(1-3):1-8.
20. Reddy S, Orenstein LAV, Strunk A, Garg A. Incidence of long-term opioid use among opioid-naive patients with hidradenitis suppurativa in the United States. JAMA Dermatol. 2019;155(11):1284-1290.
21. Lipa K, Zajac N, Witkowski G, et al. Hidradenitis suppurativa – biologic therapy and other available therapy options. Postepy Dermatol Alergol. 2023;40(4):518-528.
22. Saunte DML, Jemec GBE. Hidradenitis suppurativa: advances in diagnosis and treatment. JAMA. 2017;318(20):2019-2032.
23. Harrison BJ, Mudge M, Hughes LE. Recurrence after surgical treatment of hidradenitis suppurativa. Br Med J (Clin Res Ed). 1987;294(6570):487-489.
24. Lavogiez C, Delaporte E, Darras-Vercambre S, et al. Clinicopathological study of 13 cases of squamous cell carcinoma complicating hidradenitis suppurativa. Dermatology. 2010;220(2):147-153.
25. Lee DE, Clark AK, Shi VY. Hidradenitis suppurativa: Disease burden and etiology in skin of color. Dermatology. 2018;233(6):456-461.