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StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
Kimberly Ballard ; Victoria L. Shuman .
Last Update: May 6, 2024 .
Hidradenitis suppurativa is a chronic inflammatory skin condition characterized by painful lesions such as deep-seated nodules, abscesses, skin tunnels, and fibrotic scars. These manifestations primarily emerge in intertriginous areas, notably the axillary, groin, perianal, perineal, and inframammary regions. The condition's impact extends beyond physical discomfort, with associated pain, drainage, malodor, and scarring often leading to profound negative psychosocial implications for affected individuals.
The diagnosis of hidradenitis suppurativa is clinically based but often challenging and delayed, exacerbating the patient experience. Different grading criteria, including the Hurley classification, are available to guide treatment. Laboratory and imaging tests help characterize the lesions and rule out other conditions.
Treatment involves lifestyle modifications, medications such as antibiotics and anti-inflammatory drugs, procedures like laser therapy and excision with skin grafting. Supportive therapies like pain management and psychological support may also benefit patients. Interprofessional care is crucial to creating a personalized treatment plan, with regular follow-up appointments to monitor effectiveness and make adjustments as necessary.
This activity for healthcare professionals is designed to enhance learners' competence in evaluating and managing hidradenitis suppurativa. Participants gain profound insights into the condition's etiology, clinical presentation, complications, and therapeutic strategies. Learners become equipped to collaborate effectively within an interprofessional team to enhance outcomes for individuals with hidradenitis suppurativa.
Determine the potential triggers of hidradenitis suppurativa. Identify the clinical presentation of hidradenitis suppurativa. Implement an individualized treatment plan for patients with hidradenitis suppurativa.Apply effective strategies to improve care coordination among interprofessional team members to address complications and comorbidities for patients with hidradenitis suppurativa.
Hidradenitis suppurativa (acne inversa or Verneuil disease) is a chronic inflammatory skin condition of follicular occlusion with lesions including deep-seated nodules and abscesses, draining skin tunnels (also called sinus tracts or fistulae), and fibrotic scars.[1][2] These lesions most commonly occur in intertriginous areas, though they may present in any location with folliculopilosebaceous units. The most commonly affected areas are the axillary, groin, perianal, perineal, and inframammary regions (see Image. Hidradenitis Suppurativa, Left Axilla).[3][4]
Treatment varies based on severity and may include topical and systemic antibiotics, hormone therapy, immune modulators, and surgery.[5] This condition may have a negative psychosocial impact because of the associated pain, involvement of sensitive locations, drainage, odor, disfigurement, and scarring. Late diagnosis only worsens the patient experience.[6][7]
Skin Histology
Skin appendages include the pilosebaceous units, sweat glands, and nails, which possess distinct functions and histological features. The pilosebaceous unit is the assembly formed by the hair shaft, follicle, sebaceous gland, and arrector pili muscle. This group of skin appendages develops from the epidermis during fetal development. The hair shaft is visible on the skin's surface and is comprised of cuticle cells surrounding a cortex, with a medulla present in thicker hair. The hair follicle is essential for hair growth and is histologically divided into the infundibulum, isthmus, and inferior segment, with stem cells residing in the bulge area. Sebaceous glands are pilosebaceous unit components that produce sebum to lubricate hair. These glands have a foamy appearance microscopically due to their lipid content.
Sweat glands (sudoriferous glands) are categorized as eccrine or apocrine, which differ in their distribution and secretion mode. Eccrine glands are present in the dermis and upper hypodermis throughout the body and exhibit merocrine secretion, where the cytoplasm remains intact during secretion. Apocrine glands are found in the dermis and subcutanous fat in areas like the intertriginous zones. These glands lose the top portions of the cellular cytoplasm during secretion. Histologically, eccrine glands consist of coiled secretory segments surrounded by myoepithelial cells, while apocrine glands have less coiling and larger lumens lined by cuboidal epithelial cells.
Nails consist of the nail plate, matrix, eponychium, hyponychium, nail folds, and lunula. The matrix serves as the site of nail formation. The nail plate is composed of compact keratinocytes and lacks desquamation, contributing to its rigidity and translucency. The hyponychium lies beneath the nail plate, lacks a granular layer, and contains a rich vascular network. The eponychium serves as a pathogen barrier.[8]
The development of hidradenitis suppurativa appears to have genetic, environmental, and behavioral influences.[9] Approximately 33% to 40% of individuals with hidradenitis suppurativa report an affected first-degree relative, suggesting a hereditary component with an autosomal dominant transmission pattern.[10] Researchers have identified a loss-of-function mutation of the γ-secretase complex involved in the Notch signaling pathway in a small subset of affected families.[11] Other mutations identified in hidradenitis suppurativa include DCD (encoding dermcidin), PSTPIP1 (found in hidradenitis suppurativa syndromes), SOX9, and KLF5 genes.[12][13][14]
Environmental and behavioral factors are vital in hidradenitis suppurativa's development. Individuals with this condition often have comorbidities such as obesity, leading to increased skin friction, sweat production and retention, and hormonal changes, particularly androgen excess.[15][16] Metabolic syndrome, more prevalent in obesity, is also observed in hidradenitis suppurativa cases.[17] Smoking may exacerbate the condition, with nicotine implicated in increasing follicular plugging.[18][19] As with obesity, disease progression and severity are worse in people who smoke.[20]
Hormonal influences, signified by a higher female preponderance, menstrual cycle-related symptom fluctuations, exogenous hormone intake, and pubertal and menopausal links, have been observed.[21][22] Other potential factors include medications, bacteria, and mechanical friction.[23]
The estimated prevalence of hidradenitis suppurativa ranges from under 1% to 4%.[24] These numbers are likely underestimated because of underreporting and misdiagnosis. The condition's onset is commonly between puberty and 40 years, most frequently from ages 21 to 29. Women are about 3 times more affected than men.[25] Racial or ethnic predilection is currently unsupported, though the disease may be underreported, and studies have likely excluded black and Hispanic patients.[26][27]
Hidradenitis suppurativa's pathophysiologic mechanism starts with a defective hair follicle's occlusion and rupture, releasing keratin and bacteria into the surrounding dermis. This occlusion leads to keratinocyte proliferation and an immune response.[28][29] Neutrophilic and lymphocytic proliferation and heightened activity result in abscess formation and follicular destruction, with the involvement of adjacent tissues.[30] Additional contributors may include abnormal antimicrobial peptides, epidermal invaginations forming tracts, hormonal effects on follicular receptors, and complement pathways. Sebaceous glands also become deficient.[31][32]
Immunological abnormalities are evident in hidradenitis suppurativa. Inflammatory cytokines like tumor necrosis factor-α and interleukins are elevated in lesions, offering potential treatment targets.[33][34][35] While bacteria are not considered the primary cause, these organisms may trigger an inflammatory response. Patients may receive antibiotics for presumed infections, potentially leading to drug-resistant skin flora.[36] Aspirates from unruptured lesions typically yield sterile cultures. Bacterial infection and colonization may worsen hidradenitis suppurativa.
Hidradenitis suppurativa may be diagnosed clinically, but a skin biopsy can help confirm the diagnosis in equivocal cases. Hidradenitis suppurativa's histopathological features include:
Follicular occlusion Follicular hyperkeratosis Infundibular follicular epithelial hyperplasia Epidermal psoriasiform hyperplasia Keratin plugging Perifolliculitis (predominantly lymphocytic) Plasmocytic infiltrate Pseudoepitheliomatous hyperplasiaReports on the frequency of finding foreign body and epithelioid granulomas are conflicting, with some reporting them as frequent and others as infrequent. Eosinophils may be observed, but this finding is controversial, as studies report eosinophilic presence inconsistently.[37]
Hidradenitis suppurativa diagnosis is often delayed by an average of 7 years due to its resemblance to other conditions. Clinical diagnosis involves recognizing characteristic morphological features (nodules, tunnels, and scars), location (intertriginous areas), and chronicity.[38] Half of patients present prodromal symptoms such as burning, stinging, pain, pruritus, warmth, or hyperhidrosis, which may precede lesion appearance by 12 to 48 hours.[39] Triggers include menstruation, weight gain, stress, hormonal changes, excessive heat, and perspiration.[40] Individuals are usually well-appearing and afebrile at presentation unless secondary infection or advanced disease is present.
Characteristic primary hidradenitis suppurativa lesions are deep-seated nodules, typically 0.5 to 2 cm in size, persisting for days to months. The lesions are often mistaken for furuncles or boils and may have serosanguinous discharge, which can become purulent and malodorous. Unlike furuncles, these nodules are deep, recurrent, rupture-prone, and can form intercommunicating tunnels and tracts that may ulcerate or drain. Lidocaine injection or ultrasound examination can help visualize these tracts.[41] Advanced stages may feature thick fibrotic scars and plaques, causing architectural distortion and open comedones known as "tombstone" comedones.[42]
The axilla is the most common location for hidradenitis suppurativa lesions. Other common areas include the inguinal, inner thigh, perianal, perineal, inframammary, gluteal, pubic, scrotal, vulvar, and trunk regions. The scalp and retroauricular areas are less frequently involved (see Image. Hidradenitis Suppurativa, Groin).[43] Pertinent history includes onset typically from puberty to young adulthood, with recurrent lesions and intermittent improvement. A family history of a similar condition aids in diagnosis confirmation.
Once the history and physical exam are complete, the Hurley staging system may be used to classify the disease. This system categorizes lesions as follows:
Hurley Stage I: Abscesses lack tunnels and scars.Hurley Stage II: Recurrent abscesses have tunnels and scars, and the lesions may be single or multiple but widely separated.
Hurley Stage III: Lesions diffusely involve the skin, ie, multiple interconnected sinus tracts are present, and abscesses occupy large areas, leaving little to no uninvolved skin (see Image. Hidradenitis Suppurativa, Suprapubic Region). [44]
Hidradenitis suppurativa is a component of the follicular occlusion tetrad, along with acne conglobata, dissecting scalp cellulitis, and pilonidal sinus.[45] A diagnosis of hidradenitis suppurativa should prompt evaluation for possible cooccurrence of these conditions. Clinicians should also consider associations with metabolic syndrome, dyslipidemia, hypertension, diabetes mellitus, inflammatory bowel disease (especially Crohn disease), and spondyloarthropathy during assessment.[46] Syndromes like pyogenic arthritis, pyoderma gangrenosum, acne, suppurative hidradenitis (PAPASH) and pyoderma gangrenosum, acne suppurative hidradenitis (PASH), possibly related to a PSTPIP1 gene mutation, also warrant attention.[47]
Hidradenitis suppurativa is a clinical diagnosis. No biological or pathological diagnostic tests are required to confirm the condition. However, a biopsy may help rule out squamous cell carcinoma if the diagnosis is uncertain. Bacterial cultures are not beneficial unless a secondary infection or an alternative diagnosis is suspected. Imaging is not typically helpful, though ultrasonography may help identify skin tunneling preoperatively.[48] Severe perianal disease may warrant further imaging, preferably by magnetic resonance imaging.[49]
Guidelines recommend additional investigations to assess comorbid conditions in patients with hidradenitis suppurativa. Assessments typically involve annual physical examinations, validated screening tools, and laboratory tests. Referrals to specialists familiar with associated conditions may be necessary for further evaluation. Comorbidities in patients with hidradenitis suppurativa may include the following:
Acne vulgaris or acne conglobata Dissecting cellulitis of the scalp Pilonidal cyst Pyoderma gangrenosum Depression Suicidality Tobacco use disorder Substance use disorder Polycystic ovarian syndrome Dyslipidemia Diabetes mellitus Metabolic syndrome Hypertension Cardiovascular disease Inflammatory bowel disease SAPHO syndrome Behcet syndrome Spondyloarthritis Sexual dysfunction Down syndrome Thyroid disease Nonalcoholic fatty liver disease Obstructive sleep apnea Renal disease Sleep disturbances Alzheimer disease Herpes zoster Psoriasis vulgaris Pachyonychia congenita Dowling-Degos disease KID syndrome Cutaneous squamous cell carcinoma :[50][51]The overall treatment goals for hidradenitis suppurativa include alleviating lesion-related symptoms (eg, pain), reducing recurrence frequency and new lesion formation, and preventing disease and comorbidity progression. Treatment approaches are largely based on expert opinion and consensus due to limited comparative studies.
Treatment response assessment involves monitoring lesion frequency, severity, extent, and morphology. Quality of life changes are also evaluated using validated tools, and progression to associated comorbidities is assessed. Various scales and scoring systems, including the International Hidradenitis Suppurativa Severity Scoring System, Sartorius score, Hidradenitis Suppurativa Physician Global Assessment, and Hidradenitis Suppurativa Core Outcome Set International Collaboration, are used to measure the condition's severity and treatment outcomes.[52][53][54]
Hidradenitis suppurativa treatment should address comorbidities contributing to disease development or worsening, regardless of disease stage. Counseling and support for weight loss and smoking cessation are crucial, as obesity and smoking are associated with more severe disease progression. Minimizing skin trauma is also essential, achieved by avoiding tight clothing, harsh cleaning products, and adhesive dressings. Soft dressings with clear petroleum jelly or nonocclusive dressings can help prevent further irritation to draining lesions.[55]
Patients with hidradenitis suppurativa should be thoroughly educated about the condition's nature, wound care, and pain management. Individualized pain management plans must address potential inpatient admissions.[56][57] Hidradenitis suppurativa-related pain stems from both inflammatory and noninflammatory sources, including scarring (causing tensile pain), keloids, abscesses, open ulcerations, sinus tracts, frictional pain, lymphedema, anal fissures, and arthritis. Treatments may include topical agents like lidocaine, systemic nonsteroidal anti-inflammatory drugs, acetaminophen, atypical anticonvulsants such as gabapentin or pregabalin, and serotonin-norepinephrine reuptake inhibitors, depending on disease severity and pain type. Duloxetine may be particularly beneficial for patients with comorbid depression.[58][59]
A critically important but often overlooked aspect of treatment involves hidradenitis suppurativa's psychosocial aspect. Pain, drainage, odor, and involvement of sensitive areas reduce patients' quality of life.[60] Individuals with this condition may experience social isolation, employment difficulties due to missed work during flares, and heightened sexual or relationship dysfunction.[61] Assurance that this condition is not contagious or the result of poor hygiene can be helpful. Counseling and support groups are often beneficial additions to therapeutic plans.[62] Treatment for acute symptomatic lesions may include intralesional corticosteroid injection (usually triamcinolone), punch debridement, and topical resorcinol.[63][64][65] Incision and drainage is not recommended.[66]
Topical antibiotics are the first-line treatment for early uncomplicated disease. Topical clindamycin has been proven the most effective and may be an appropriate adjunctive treatment to oral therapy.[67] Hurley stage I disease without skin tunneling or scarring may be treated with oral tetracycline antibiotics (eg, doxycycline), antiandrogen agents (eg, spironolactone), and metformin.[68] Tetracyclines should be discontinued and other agents retained if patient response is satisfactory after 2 to 3 months. Another tetracycline trial should be initiated if improvement occurs but is unsatisfactory. Switching to a combination of oral clindamycin and rifampin, dapsone, or acitretin may be considered if the clinical response remains unsatisfactory after 2 to 3 months on the same regimen or a 2nd tetracycline trial.[69][70]
The initial treatment for Hurley stages II and III is similar to that of Hurley stage I disease. Potential treatment reactions must be considered during therapeutic planning. Patients should be educated on these medications' adverse effects before starting their regimen.
Surgical or biologic therapy should be considered if the patient poorly responds after 2 to 3 months of initial therapy, fails a 2- to 3-month second therapeutic trial, or a Hurley stage I case is treatment-refractory.[71]
The preferred biologic agent for hidradenitis suppurativa is adalimumab, as it is backed by extensive research. Secukinumab, infliximab, or acitretin are alternatives. Etanercept has not shown efficacy in treating this condition.[72][73][74] The treatment must be continued if the patient demonstrates progressive improvement after 3 to 4 months of biologic therapy. Oral antiandrogen agents and metformin may be used as adjuncts.[75]
Switching to a different class of biologics is advised if the response is unsatisfactory, followed by reassessment in 3 to 4 months for continued treatment or consideration of alternatives.[76][77] Surgical management and adjunctive therapies like intravenous ertapenem may be considered for severe, refractory hidradenitis suppurativa. Localized laser and pulsed light therapy may be offered as an option to disrupt the inflammatory process.[78][79][80]
Surgical management may be pursued at any stage to remove areas of active disease and limit complications, but it should be combined with medical therapy. Preoperative management should include antibiotics, anti-inflammatory agents (eg, biologics or cyclosporine), and corticosteroids (eg, prednisone or glucocorticoids).[81] Local procedures include punch debridement, deroofing, or wide excision. Punch debridement uses a 5- to 7-mm circular punch biopsy tool to evacuate an inflamed lesion. The lesion is left to heal by secondary intention with a petrolatum dressing after achieving hemostasis. Deroofing involves entering skin tunnels and sequentially removing their roofs using scissors or a carbon dioxide laser.[82]
Wide excision with reconstruction may be performed to debride a lesion until only the subcutaneous fat remains. Primary closure or a larger flap may be used for repair, depending on the anatomic location.[83] Grafting, which involves debriding the affected subepidermal skin and recycling the epidermis as a skin graft, may also be considered. Negative pressure wound therapy has also been used.[84] Petrolatum nonadherent dressings are recommended postoperatively to avoid friction. However, patients should be cautioned about the risks of bleeding, infection, or new disease when using these dressings.[85]
Other therapies that may be considered include neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, ustekinumab, anakinra, bimekizumab, guselkumab, canakinumab, cyclosporine, tacrolimus, apremilast, zinc, photodynamic therapy, golimumab, risankizumab, liraglutide, microwave ablation (not currently recommended), cryoinsufflation, botulinum toxin injections, and ionizing radiation.
The following conditions should be ruled out when diagnosing hidradenitis suppurativa:
