Three diagnostic criteria must be met for hidradenitis suppurativa: typical lesions, occurrence in one or more of the predilection areas, and that it is chronic and/or recurrent. Several outcome measures are used, including patient-reported pain and itch scales, Dermatology Life Quality Index, and Skindex. Hidradenitis suppurativa is associated with significant comorbidities that must be addressed in the evaluation of the patients.
Key points
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Hidradenitis suppurativa (HS) is a clinical diagnosis.
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Three diagnostic criteria must be met: (1) typical lesions, that is, deep-seated painful nodules; (2) typical location, that is, the disease must occur in 1 or more of the predilection areas, including axillae, inframammary and intermammary folds, groin, perineal region, or buttocks; and (3) typical evolution, that is, a chronic and/or recurrent disease.
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Recommended overall outcome measures include general patient-reported outcome measures such as patient-reported pain and itch scales, Dermatology Life Quality Index, and Skindex.
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HS is associated with significant comorbidities; in particular, metabolic syndrome and depression, which must be addressed in the evaluation of the patient.
Hidradenitis suppurativa (HS) is a clinically defined disease, with no pathognomonic tests. This is not unique among dermatologic diseases but this requires clearly stated criteria. It may contribute to the significant diagnostic and, consequently, therapeutic delay many patients experience. In addition to diagnosis, research and patient management also benefit from standardized and validated outcome reporting. Although consensus has been reached on the diagnostic criteria, the outcomes reported still vary considerably. The explicit use of the definitions and outcome measures described in this article is recommended in future studies.
Diagnosis
The diagnosis is given by the modified Dessau definition, describing diagnostic lesions, topography, and history of the disease. Although the modified Dessau definition is usually straightforward, the terminology used to describe HS has not been consistent throughout the literature.
Three criteria must be present:
- 1.
Typical lesions, that is, deep-seated painful nodules. These are often described as blind boils in the early lesions because they do not have a purulent point, presumably due to their deeper location in the dermis. Other lesions that are commonly described are: abscesses; bridged scars; draining sinus (inflamed tunnels); and postinflammatory, open, tombstone double-ended comedones (pseudocomedones). Patients often indiscriminately describe the lesions as boils. Usually, multiple elements are present that facilitate the diagnosis. It is, however, important to avoid confusion with nondiagnostic elements, such as simple folliculitis, when making the diagnosis.
- 2.
These disease must occur in 1 or more of the predilection areas: axillae, inframammary and intermammary folds, groin, perineal region, or buttocks. Lesions may appear elsewhere, as in ectopic HS, but the predilection areas must also be involved to make the diagnosis.
- 3.
Chronicity and recurrence are important elements of the history. Temporary lesions initially recur in the predilection areas. The initial lesions progress to more chronic lesions and new lesions are added. Arbitrarily, 2 recurrences in 6 months has been used as a diagnostic criterion.
All 3 criteria must be present for the definitive diagnosis and, because of the diagnostic requirement for recurrence and chronicity, an observation period may be necessary before the definitive diagnosis is made. If, for example, there is no history of recurrence and chronicity, there may be some delay in the diagnosis, which should not exceed 6 months by definition.
Several other factors may support the diagnosis but are not pathognomonic or part of the clinical definition. Familial history of HS, recurrent inflammatory uncharacteristic lesions (eg, folliculitis, open comedones) in a typical location, typical lesions in atypical location (usually pressure points and locations of enhanced mechanical friction, such as thighs or belt region of the abdomen), presence or history of a pilonidal sinus, and absence of pathogenic microbes on routine culture.
The clear clinical presentation (painful lesions recognized by patients as boils), the easily defined areas that must be affected, and the recurrent and chronic nature of the disease are sufficient for self-reported diagnosis, with a sensitivity of 90% and a specificity of 97%.
Diagnosis
The diagnosis is given by the modified Dessau definition, describing diagnostic lesions, topography, and history of the disease. Although the modified Dessau definition is usually straightforward, the terminology used to describe HS has not been consistent throughout the literature.
Three criteria must be present:
- 1.
Typical lesions, that is, deep-seated painful nodules. These are often described as blind boils in the early lesions because they do not have a purulent point, presumably due to their deeper location in the dermis. Other lesions that are commonly described are: abscesses; bridged scars; draining sinus (inflamed tunnels); and postinflammatory, open, tombstone double-ended comedones (pseudocomedones). Patients often indiscriminately describe the lesions as boils. Usually, multiple elements are present that facilitate the diagnosis. It is, however, important to avoid confusion with nondiagnostic elements, such as simple folliculitis, when making the diagnosis.
- 2.
These disease must occur in 1 or more of the predilection areas: axillae, inframammary and intermammary folds, groin, perineal region, or buttocks. Lesions may appear elsewhere, as in ectopic HS, but the predilection areas must also be involved to make the diagnosis.
- 3.
Chronicity and recurrence are important elements of the history. Temporary lesions initially recur in the predilection areas. The initial lesions progress to more chronic lesions and new lesions are added. Arbitrarily, 2 recurrences in 6 months has been used as a diagnostic criterion.
All 3 criteria must be present for the definitive diagnosis and, because of the diagnostic requirement for recurrence and chronicity, an observation period may be necessary before the definitive diagnosis is made. If, for example, there is no history of recurrence and chronicity, there may be some delay in the diagnosis, which should not exceed 6 months by definition.
Several other factors may support the diagnosis but are not pathognomonic or part of the clinical definition. Familial history of HS, recurrent inflammatory uncharacteristic lesions (eg, folliculitis, open comedones) in a typical location, typical lesions in atypical location (usually pressure points and locations of enhanced mechanical friction, such as thighs or belt region of the abdomen), presence or history of a pilonidal sinus, and absence of pathogenic microbes on routine culture.
The clear clinical presentation (painful lesions recognized by patients as boils), the easily defined areas that must be affected, and the recurrent and chronic nature of the disease are sufficient for self-reported diagnosis, with a sensitivity of 90% and a specificity of 97%.
Outcomes
Morbidity is assessed in 3 ways.
Clinical Assessment
Two types of disease severity markers are evaluated:
- 1.
The physical signs, that is, cutaneous changes due to the disease (eg, inflamed nodules and scars)
- 2.
An activity index (number of nodules, abscess, importance of pain, and suppuration) at a point in time or over a specified period.
These 2 aspects of morbidity are not necessarily correlated and may, in consequence, not follow a parallel evolution, suggesting that they need to be assessed separately.
Patient-reported Outcomes Measures
The use of patient-reported outcomes measures (PROMs) is generally acknowledged as a practical method to gauge the psychological consequences of the disease. Standard questionnaires on dermatologic quality of life, such as the Dermatology Life Quality Index and the Skindex, have been used to quantify the overall morbidity. Similarly, visual analogue scales or numeric rating scales of pain and itch are highly relevant PROMs.
Imaging and Biochemistry Studies
Classic clinical photography, using standardized photography, is useful for documentation of color, overall surface anatomy, and visible details. However, these poorly represent dermal and subcutaneous changes. These are better identified by high-frequency ultrasound as described by Wortsman. MRI is also a suitable method, especially for the imaging of differential diagnosis, such as fistulae.
No pathognomonic test exists but disease activity may be reflected by changes in C-reactive protein levels and leukocyte counts. Several other disease markers have been proposed but are neither routinely used nor generally available currently.
Clinical assessment
Hurley Staging
Proposed by Dr H Hurley in 1989 while describing surgical therapy, the stages are
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I: Abscess formation, single, or multiple, without sinus tracts and cicatrisation
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II: Recurrent abscesses with tract formation and cicatrisation, single or multiple, widely separated lesions
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III: Diffuse or near-diffuse involvement, or multiple interconnected tracts and abscesses across the entire area.
Stage I disease is thought to be the most common. Most patients presenting for treatment, however, have stage II disease.
The Hurley classification has been designed to describe the severity of involvement of 1 region for surgical purpose. It cannot be used to evaluate the severity of a whole patient. In practice, however, it is frequently used as a patient’s severity index to justify decisions on treatment. The scale does not reflect the current activity of the disease. It is lacking any assessment of the inflammation inherent in the disease and, instead, focuses only on consequences of the disease, that is, late changes such as scarring and tunnels. It seems mainly useful for systematic description of the earlier disease evolution.
Sartorius Score and Modified Sartorius Score
A more dynamic HS score that includes assessments of nodules, which may be transient, was created by Sartorius and colleagues and later modified and partly validated. The original Sartorius score was based on lesion counts and included scars and pustules. In the modified Sartorius score, only major characteristic elements are counted. These include nodules and tunnels (fistulas). In both, versions the longest distance between 2 lesions in a region is measured as a surrogate of the area involved and extra points are given to Hurley classification criteria of involvement of 3 areas. The lesional counting makes the score difficult to use in cases of advanced disease in which multiple lesions merge into plaques. In contrast, mild HS can be measured comfortably in a routine clinical setting after the assessor has achieved some familiarity with the score. The modified Sartorius score is commonly used in clinical trials.
Physician Global Assessment
An HS-specific physician global assessment (PGA) containing 6 categories has been used in trials. The categories describe the stages of HS:
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Clear: no inflammatory or noninflammatory nodules
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Minimal: only noninflammatory nodules are present
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Mild: fewer than 5 inflammatory nodules without abscesses and draining fistulas, or 1 abscess or draining fistula without additional inflammatory nodules
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Moderate: fewer than 5 inflammatory nodules or 1 abscess, or draining fistula and 1 or more inflammatory nodules, or 2 to 5 abscesses or draining fistulas and less than 10 inflammatory nodules
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Severe: 2 to 5 abscesses or draining fistulas and 10 or more inflammatory nodules
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Very severe: more than 5 abscesses or draining fistulas.
The PGA considers only inflammatory lesions, namely inflammatory nodules, abscesses, and fistulas. It is well adapted in clinical practice to the management of patients receiving medical treatments. The PGA has not been used to classify populations in descriptive studies.
The Hidradenitis Suppurativa Severity Index
This score is not often used, and combines categorical objective and subjective parameters. The HS Severity Index Score has been used in 2 studies of the efficacy of infliximab.
Related posts:
Prevalence, Risk Factors, and Comorbidities of Hidradenitis Suppurativa
The Handicap of Hidradenitis Suppurativa
The Genetics of Hidradenitis Suppurativa
Inflammatory Mechanisms in Hidradenitis Suppurativa
Randomized Controlled Trials for the Treatment of Hidradenitis Suppurativa
Imaging of Hidradenitis Suppurativa
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