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Hidradenitis
View on Wikipedia| Hidradenitis | |
|---|---|
| Specialty | Dermatology |
Hidradenitis is any disease in which the histologic abnormality is primarily an inflammatory infiltrate around the eccrine glands.[1]: 780 This group includes neutrophilic eccrine hidradenitis and recurrent palmoplantar hidradenitis.[1]: 780
It can also be defined more generally as an inflammation of sweat glands.[2]
Hidradenitis suppurativa is a chronic cutaneous condition originally thought to be primarily characterized by suppurative inflammation of the apocrine sweat glands.[3]: 710 Recent evidence supports that the primary event is follicular hyperkeratosis and obstruction,[4] but the term hidradenitis supperativa has continued to be used in major medical journals.[5]
Symptoms
[edit]Hidradenitis suppurativa is a chronic inflammatory skin condition, considered a member of the acne family of disorders.[6] It is sometimes called acne inversa. The first signs of HS are small bumps on the skin that resemble pimples, cysts, boils, or folliculitis. As the disease progresses and abscesses reoccur, they become larger and more painful; eventually tunnels of scar tissue connect the lesions. These lesions may open up if they become too enlarged and drain bloodstained pus.[7]
Risk factor
[edit]One risk factor is age; HS usually starts after puberty, usually in the teens and twenties.[8] The condition is much more common in women than in men but is usually more serious and debilitating in men. Other associated conditions include obesity, diabetes, metabolic syndrome, arthritis, acne, and other inflammatory disorders. Early diagnosis of this disease is very important to decrease the number of flares, pain, and discomfort.[7]
Treatment
[edit]The Mayo Clinic suggests the following: antibiotics (generally the lowest side effect profile compared to other treatments); corticosteroids (e.g., prednisone); but corticosteroids have many side effects, including "moon face" for the duration of the medication's trial usage, as well as unwanted hair growth for females and/or osteoporosis with long-term use. Tumor necrosis factor (TNF)-alpha inhibitors like infliximab (Remicade) and adalimumab (Humira) have shown promise for some, but they should probably be considered a third-line treatment, as treatment is associated with increased risk of infection, heart failure and certain cancers. Surgery is also available for those overwhelmed by the condition, but it will not cure the condition, just relieve the skin-related issues for a while. The disease is pernicious and is almost always guaranteed to return, if not in the same spot where the surgery was performed.[9]
Some products for adult acne may help relieve some symptoms for people with hidradenitis, although there is no guarantee it will work in all or even most individuals. Birth control medication may relieve some symptoms for women; there is a hormonal treatment for men as well, but that has not been proven to be safe or effective as of yet.[10]
Alternative treatments not approved by the FDA include alpha hydroxy acids (naturally available in small amounts in citrus fruits), Azelaic acid, and zinc. It is not thought that they are as effective as standard medical treatment, but they tend to have less side effects. Some suggest tea tree oil and a specific strain of brewer's yeast, called CBS 5926. However, tea tree oil can cause contact dermatitis for some as well as breast development in teenage boys and should not be used if one has rosacea due to the potentiality of worsening the symptoms of that skin condition. CBS 5962 can also cause migraines and intestinal issues for some.[11]
See also
[edit]References
[edit]- ^ a b James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. ISBN 0-7216-2921-0.
- ^ "hidradenitis" at Dorland's Medical Dictionary
- ^ Freedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. ISBN 0-07-138076-0.
- ^ Sellheyer K, Krahl D (July 2005). ""Hidradenitis suppurativa" is acne inversa! An appeal to (finally) abandon a misnomer". Int. J. Dermatol. 44 (7): 535–40. doi:10.1111/j.1365-4632.2004.02536.x. PMID 15985019. S2CID 34144101.
- ^ Saunte D, Jemec, G (Nov 18, 2017). "Hidradenitis Suppurativa: Advances in Diagnosis and Treatment". JAMA. 318 (20): 2019–2032. doi:10.1001/jama.2017.16691. PMID 29183082. S2CID 5017318.
- ^ staff, familydoctor org editorial. "Hidradenitis Suppurativa". familydoctor.org. Retrieved 2021-11-19.
- ^ a b Revuz, J. E., Canoui-Poitrine, F., Wolkenstein, P., Viallette, C., Gabison, G., Pouget, F., ... & Grob, J. J. (2008). Prevalence and factors associated with hidradenitis suppurativa: results from two case-control studies. Journal of the American Academy of Dermatology, 59(4), 596-601.
- ^ "Hidradenitis Suppurativa". medlineplus.gov. Retrieved 2021-11-19.
- ^ Mayo Clinic: Hidradenitis suppurativa support
- ^ Birth Control Pills for Certain Female Skin-Related Issues
External links
[edit]Hidradenitis
View on GrokipediaSigns and symptoms
Lesion types
Hidradenitis suppurativa manifests through a spectrum of primary skin lesions that typically begin as deep-seated, inflammatory nodules measuring 0.5 to 2 cm in diameter, often described as pea-sized and resembling boils.[1] These nodules are erythematous, firm, and intensely tender to palpation, arising from follicular occlusion and subsequent inflammation in apocrine gland-bearing skin.[1] They may persist for days to months before potentially rupturing, releasing serosanguinous or purulent, malodorous discharge.[1] Secondary lesions develop as complications of unresolved primary nodules, progressing to abscesses characterized by collections of pus within fluctuant, swollen masses that exacerbate local inflammation.[1] Rupture of these abscesses can lead to the formation of draining sinus tracts or tunnels, which are subcutaneous passages that intermittently discharge purulent material and contribute to chronicity.[10] These manifestations can be particularly evident in the breast region, where deep subcutaneous nodules or abscesses may rupture, drain pus, form sinus tracts, and heal with ropelike, pitted, or atrophic scarring resembling acne scars.[1][2] Following resolution of active inflammation, fibrotic scarring occurs, resulting in thick, rope-like bands, pitted, or atrophic scarring that may resemble acne scars, or hypertrophic plaques that distort the skin's architecture.[1][2] Distinctive comedonal structures in hidradenitis suppurativa include open "tombstone" comedones, which represent dilated follicular ostia filled with keratin plugs, and double-ended pseudocomedones, which appear as paired, blackhead-like lesions connected by a subcutaneous tract unique to the intertriginous areas affected by the disease.[1]30902-7/fulltext) These pseudocomedones arise from the rupture and reformation of follicular units, differing from typical acne comedones due to their bidirectional drainage.[11] The sensory experience of these lesions is dominated by intense pain, stemming from acute inflammatory processes that release cytokines and from mechanical pressure exerted by expanding nodules and abscesses on underlying nerves.[12] This nociceptive and potentially neuropathic pain can radiate beyond the lesion site, described by patients as throbbing or burning, and significantly impairs daily function.02814-7/fulltext) In advanced cases, persistent sinus tracts may evolve into chronic tunnels, perpetuating cycles of pain and discharge.[1]Disease progression
Hidradenitis suppurativa typically begins with acute flares characterized by the development of painful nodules or abscesses in intertriginous areas, which often resolve spontaneously within 1 to 4 weeks.[13] These early lesions, such as single or multiple abscesses without sinus tracts or scarring, correspond to Hurley stage I and may be followed by periods of remission lasting weeks to months, during which symptoms subside completely or nearly so.[14] As the disease progresses to a chronic phase, flares become more recurrent, leading to the formation of persistent sinus tracts and fistulas that connect lesions beneath the skin, resulting in ongoing induration and purulent drainage. This corresponds to Hurley stage II, where recurrent abscesses are accompanied by widespread sinus tracts and scarring, and in advanced Hurley stage III, the involvement becomes diffuse with multiple interconnected tracts causing extensive fibrosis. The frequency of flares varies widely, from infrequent episodes in mild cases to near-daily drainage and active inflammation in severe, longstanding disease.[15][16] Repeated inflammation over time drives the scarring process, producing either hypertrophic scars—raised, firm plaques or rope-like bands—or atrophic scars, which appear as depressed, smooth, or cribriform depressions in the skin.30234-6/fulltext)[17] In severe cases, these scars can lead to contractures that restrict skin mobility and cause functional impairment.[18]Affected body areas
Hidradenitis suppurativa predominantly involves intertriginous regions rich in apocrine glands, where the skin folds create an environment conducive to disease manifestation. The axillae represent the most common site of involvement, followed by the inguinal folds, perianal and perineal areas, inframammary folds, breasts, and buttocks.[1][7] HS can affect the breast skin itself in addition to the inframammary folds, often presenting as deep painful nodules or abscesses accompanied by pitted or atrophic scarring on the breast skin that may resemble acne scars.[2][19] Less frequently affected areas include the upper chest, back, and extremities, with rare occurrences on the face or ears.[7] The distribution is typically bilateral and symmetrical, reflecting the anatomical symmetry of apocrine gland-bearing skin.[20] Mechanical factors, such as friction and occlusion within skin folds, play a key role in site predilection and exacerbation, particularly in areas prone to rubbing like the groin and axillae.[7] These influences are more pronounced in individuals with higher body mass index, leading to increased involvement of flexural sites.[1]Causes and risk factors
Genetic predispositions
Hidradenitis suppurativa (HS) exhibits a significant hereditary component, with approximately 30% to 40% of patients reporting a positive family history of the disease.[21] This familial clustering is observed across various studies, including pediatric cohorts where up to 41% of cases show inheritance patterns.[22] In affected families, the condition often follows an autosomal dominant inheritance with incomplete penetrance, meaning not all individuals carrying the genetic variant develop HS.[22] This pattern underscores the role of genetic susceptibility, though monogenic forms account for only a minority of cases, estimated at less than 7%.[23] Recent genome-wide association studies (GWAS) as of 2024 have identified 11 significant risk loci for HS, with 7 novel signals, highlighting a polygenic architecture involving pathways like Notch and Wnt/β-catenin signaling.[24] Additionally, a 2025 multi-population GWAS confirmed associations near the HLA region, supporting an autoimmune component in non-monogenic cases.[25] Gain-of-function variants in the KDF1 gene have also been linked to HS associated with ectodermal dysplasia.[26] Key genetic associations involve mutations in genes encoding components of the γ-secretase complex, which regulates Notch signaling essential for skin and hair follicle development. Specifically, loss-of-function mutations in NCSTN (nicastrin), PSENEN (presenilin enhancer), and PSEN1 (presenilin 1) have been identified in rare familial forms of HS, with NCSTN mutations being the most common, reported in about 54.5% of such cases.[27] These mutations disrupt γ-secretase activity, leading to impaired Notch pathway function and increased susceptibility to follicular occlusion and inflammation.[22] Additionally, polymorphisms in the promoter region of the TNF gene, such as the -238 variant, are associated with increased disease susceptibility and influence response to anti-TNF therapies.[28] Heritability estimates from twin studies further highlight the strong genetic basis of HS. A large Dutch cohort of over 4,600 twins reported a narrow-sense heritability of 77% (95% CI, 54%-90%), with monozygotic twin concordance at approximately 31% compared to 8% in dizygotic twins.[29] Similarly, a Danish nationwide twin registry study found monozygotic concordance of 28% (95% CI, 7%-49%), yielding a familial risk 73 times higher than the background population, supporting heritability around 80%.[30] These findings indicate that genetic factors explain the majority of HS variance, though environmental interactions modulate expression. Ethnic variations in HS prevalence also suggest genetic influences, with higher rates observed in individuals of African descent. Studies report an average prevalence of 1.3% among African Americans, compared to 0.07% in Hispanics/Latinos and intermediate levels in Caucasians, pointing to potential ancestry-specific genetic risk factors.[31] Genome-wide association studies have identified variants near genes like SOX9 and KLF5 that may contribute to this disparity, particularly in populations with African ancestry.[32]Lifestyle and environmental triggers
Obesity is a significant modifiable risk factor for hidradenitis suppurativa (HS), with individuals having a body mass index (BMI) greater than 30 kg/m² exhibiting approximately a three-fold increased risk compared to those with lower BMI, primarily due to increased skin friction in intertriginous areas that promotes follicular occlusion and inflammation.[33] This association is further supported by higher average BMI values among HS patients (around 27.5 kg/m²) versus controls, correlating with greater disease severity.[34] Smoking substantially elevates HS risk and worsens its course, with tobacco use approximately doubling the incidence rate (0.20% in smokers versus 0.11% in non-smokers) and current smokers demonstrating more severe disease, as measured by higher pack-years and odds ratios up to 4.16 for disease development.[35][34] Hormonal factors contribute to HS onset and flares, with the condition typically emerging post-puberty due to androgen-driven apocrine gland activity, and many women (43–76.7%) reporting symptom exacerbation during menstrual cycles linked to estrogen and progesterone fluctuations.[36] Additionally, HS patients face a 2.64-fold higher risk of polycystic ovary syndrome (PCOS), which involves hyperandrogenism that may amplify disease activity.[36] Common environmental triggers include excessive sweating (hyperhidrosis), which precedes lesions by 12–48 hours and fosters a moist environment conducive to bacterial proliferation, as well as tight clothing that induces mechanical friction and irritation in affected areas.[1] Depilation methods such as shaving or waxing can precipitate flares by causing microtrauma to hair follicles, while bacterial overgrowth, particularly involving Staphylococcus species, exacerbates inflammation despite not being the primary etiology.[1][34] Observational studies suggest dietary associations with HS flares, including higher intake of dairy products (e.g., cheese and yogurt, averaging 222 g/day in patients versus 188 g/day in controls) correlating with increased severity, though causation remains unproven.[37] Similarly, elevated consumption of nightshade vegetables (e.g., tomatoes, potatoes; 237 g/day in patients versus 190 g/day in controls) appears in cross-sectional data but lacks strong evidence for direct causality and shows no clear link to disease staging.[37]Pathophysiology
Follicular occlusion mechanism
The follicular occlusion mechanism in hidradenitis suppurativa (HS) is initiated by hyperkeratinization of the follicular epithelium, particularly at the infundibulum, which leads to the formation of keratin plugs that obstruct the pilosebaceous unit.[13] This plugging causes progressive dilation of the follicle, culminating in rupture and the release of accumulated contents into the surrounding dermis.[38] The process is considered the primary structural event driving disease onset, distinct from inflammatory responses that follow.[39] Apocrine glands, located in intertriginous areas such as the axillae and groin, empty their secretions directly into the upper portion of the hair follicle canal, above the sebaceous gland duct.[40] In the context of follicular occlusion, these glandular secretions mix with keratin debris and sebum within the obstructed infundibulum, contributing to the development of comedone-like structures that exacerbate plugging. Although apocrine glands are anatomically proximate and secondarily involved, the primary pathology originates from the follicle rather than glandular dysfunction itself.[38] Bacterial involvement in the follicular occlusion mechanism occurs as a secondary phenomenon, with anaerobes such as Prevotella species colonizing the dilated and ruptured follicles after initial obstruction.[41] These bacteria do not initiate the occlusion but proliferate in the anaerobic environment created by the keratin plug, potentially amplifying tissue damage through chronic infection.[42] Studies of lesional microbiology confirm that such colonization is polymicrobial and opportunistic, supporting the view that bacteria play a supportive rather than causal role.[41] Histological examination of early HS lesions reveals dilated hair follicles filled with keratin plugs, often accompanied by mild perifollicular inflammation, as observed in biopsies from pre-abscess stages.[43] These findings, including infundibular hyperkeratosis and epithelial hyperplasia, confirm the occlusion as the inciting event, with rupture evident in subsequent sections.[44] Such early biopsies underscore the mechanical nature of the process before widespread inflammatory infiltration.[13]Inflammatory processes
Hidradenitis suppurativa (HS) involves dysregulated immune responses that escalate beyond initial follicular occlusion, primarily through overactivation of T helper 1 (Th1) and Th17 pathways in lesional skin. This dysregulation leads to elevated levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-17 (IL-17), and interleukin-1 beta (IL-1β), which are significantly higher in HS lesions compared to healthy skin.[45][46] These cytokines drive a self-perpetuating inflammatory cycle, promoting keratinocyte hyperproliferation and immune cell infiltration.[47] Follicular plugging serves as the initial trigger for this immune escalation.[48] The auto-inflammatory aspects of HS feature prominent neutrophil recruitment, resulting in abscess formation and tissue destruction. Neutrophils infiltrate early lesions, releasing neutrophil extracellular traps (NETs) that amplify inflammation and contribute to the formation of painful subcutaneous abscesses.[39] In chronic stages, epithelialized tunnels harbor bacterial biofilms, which sustain persistent inflammation by evading immune clearance and promoting recurrent flares.[49] These biofilms, often involving staphylococcal species, correlate with higher inflammatory activity in longstanding lesions.[50] Systemic involvement manifests in severe HS cases through elevated acute-phase reactants like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), reflecting broader inflammatory burden.[51] These markers increase with disease severity, as measured by Hurley staging, and are associated with comorbidities such as metabolic syndrome, including obesity and dyslipidemia.[52] Patients with HS exhibit higher rates of metabolic derangements, potentially exacerbating systemic inflammation via adipokine dysregulation.[53] A genetic-immunologic link underlies this inflammation, particularly through gamma-secretase mutations that impair keratinocyte differentiation and enhance signaling pathways. Mutations in genes encoding the gamma-secretase complex, such as NCSTN and PSENEN, disrupt Notch signaling, leading to defective follicular epithelium and increased susceptibility to inflammatory triggers.[54] This impairment promotes aberrant cytokine production and immune cell activation, bridging genetic predisposition to the chronic inflammatory state in HS.[55]Diagnosis
Clinical evaluation
The clinical evaluation of hidradenitis suppurativa (HS) begins with a detailed patient history to identify characteristic features of the disease. Patients typically report recurrent, painful lumps or nodules in intertriginous areas, such as the axillae, groin, or inframammary regions, with lesions persisting for more than two weeks and recurring over months or years.[1] A family history is noted in approximately 30-40% of cases, highlighting a genetic component, while risk factors like smoking (prevalent in 70-90% of patients) and obesity are commonly elicited to guide counseling.[56] These historical elements help establish chronicity and recurrence, essential for diagnosis.[57] Physical examination involves thorough inspection and palpation of affected areas to confirm the presence of typical lesions. Inspection reveals deep-seated nodules (0.5-2 cm in size), abscesses, sinus tracts, and fibrotic scars in apocrine gland-bearing sites, often with evidence of drainage or tunneling.[1] Palpation assesses for tenderness, fluctuance indicating abscess formation, and the extent of subcutaneous involvement, which may not be fully apparent on visual exam alone.[56] This step is crucial for documenting lesion morphology and distribution, aiding in differentiation from acute conditions.[57] Basic laboratory tests support the evaluation by assessing for inflammation or secondary infection. A complete blood count (CBC) may show leukocytosis if infection is present, while elevated C-reactive protein (CRP) levels indicate active inflammatory processes.[1] In early or mild cases, ultrasound can detect subclinical sinus tracts or fluid collections, enhancing diagnostic accuracy without invasive procedures.[56] Diagnosis of HS relies on clinical criteria proposed in expert guidelines, requiring at least three key elements: characteristic lesions (e.g., recurrent nodules, abscesses, or draining sinus tracts), typical anatomic locations (e.g., axillae, groin, perineum), and chronicity with recurrence over at least six months.[57] These criteria achieve high sensitivity (around 90%) and specificity (97%) for confirming HS based on history and exam alone.[56] Once diagnosed, severity staging, such as the Hurley system, may be applied to guide management.[1]Differential diagnoses
Hidradenitis suppurativa (HS) can be challenging to diagnose due to its resemblance to several other dermatologic and systemic conditions, particularly in early stages where painful nodules and abscesses predominate. Accurate differentiation relies on clinical history, lesion distribution in intertriginous areas, chronic recurrence, and progression to sinus tracts and scarring, which are hallmarks of HS not typically seen in acute infections.[1][58] Common mimics include folliculitis, which presents as superficial, perifollicular pustules that resolve quickly with or without antibiotics, lacking the deep nodules and chronicity of HS.[1] Furunculosis, often caused by Staphylococcus aureus, manifests as single or isolated deep-seated lesions that respond promptly to incision and drainage or antibiotics, without the multifocal, recurrent pattern in apocrine gland-bearing areas characteristic of HS.[1][58] Crohn's disease, particularly in perianal involvement, may produce fistulas and abscesses mimicking HS, but is distinguished by associated gastrointestinal symptoms such as diarrhea or abdominal pain, and biopsy findings of non-caseating granulomas.[1][59] Other conditions to consider include tuberculosis, which can form cold abscesses with systemic symptoms like weight loss and night sweats, confirmed by acid-fast bacilli on culture or biopsy, unlike the localized, non-febrile course of uncomplicated HS.[1] Actinomycosis presents with chronic suppurative infections featuring sinus tracts and sulfur granules on histopathology, often with systemic involvement, differentiating it from HS through microbiologic evidence.[1] Epidermal cysts appear as solitary, non-recurring encapsulated masses that do not form interconnecting tracts, readily identified by imaging or surgical exploration.[1] Squamous cell carcinoma may simulate advanced HS with ulcerative, indurated growths, but is suspected in cases of atypical rapid progression or non-healing wounds, requiring biopsy for keratinizing features.[1] When HS involves the breast area, presenting with deep lumps accompanied by acne-like marks or scarring on the breast skin, it must be differentiated from breast cancer (particularly inflammatory breast cancer, which typically features rapid-onset erythema, peau d'orange skin texture, dimpling, and nipple retraction or inversion rather than recurrent suppurative nodules and pitted or bridged scarring), as well as infectious mastitis, breast abscesses, or cysts. Prompt medical evaluation is essential to rule out malignancy through clinical examination, imaging, and biopsy if indicated, as HS is a clinical diagnosis.[19][60][61] HS generally lacks fever or systemic signs unless secondarily infected, contrasting with infectious mimics that often involve acute inflammatory responses and resolution upon antimicrobial therapy.[58] Alternative diagnoses should be suspected in atypical presentations, such as lesions outside intertriginous sites (e.g., face or extremities), rapid onset without recurrence, or isolated response to antibiotics without scarring.[1][58]Staging and classification
Hurley staging system
The Hurley staging system, introduced in 1989 by H.J. Hurley, classifies hidradenitis suppurativa (HS) severity into three stages based on the anatomical extent of lesions, presence of sinus tracts, and scarring.[62] This simple, clinician-applied tool focuses on observable structural changes rather than subjective symptoms, making it a foundational assessment in dermatology.[5] The stages are defined as follows:| Stage | Description |
|---|---|
| I | Single or multiple abscesses without sinus tracts or scarring, limited to one area.[5] |
| II | Recurrent abscesses with sinus tracts and scarring, featuring widely separated lesions.[5] |
| III | Diffuse involvement with multiple interconnected sinus tracts and abscesses across an entire area.[5] |
