HS Damage May Begin Early and Progress Over Time
The majority of patients with hidradenitis suppurativa (HS) have Hurley Stage II at the time of diagnosis, meaning sinus tracts and scarring may have already formed.1,2 One study showed that one-third of those who received an earlier diagnosis at Hurley Stage I already had subclinical sinus tract development.2
As the disease goes undetected or untreated, HS progresses to the formation of extensive sinus tracts, some of which can extend into deeper tissue, including muscle, fascia, and lymph nodes. Assessing sinus tract involvement, scar tissue formation, and psychosocial implications are important aspects of determining disease severity.2,3
52% of HS patients experienced disease progression in 1 or more regions within 2 years in the UNITE registry (N=318).4*
*UNITE: a prospective disease-based registry of patients ≥12 years with active HS. Disease progression defined as a shift in Hurley Stage to a higher stage in any anatomic region compared with baseline (excluding shifts from Hurley 0 to Hurley I).
Hurley Stage I
Patient 1: Ultrasound shows dilation of hair follicles2
A Chilean study sought to examine the morphological characteristics of HS using 3D ultrasound to visualize early anatomical changes in HS regions, which may allow the identification of lesions that may benefit from earlier medical treatment and possibly prevent the development of sinus tracts. In this study, ultrasound imaging demonstrated that one-third of patients classified by a certified dermatologist as Hurley Stage I (n=6) were shown to have subclinical sinus tracts.2
Ultrasound shows distortion of the hair follicle preceding perifollicular edema, suggesting that inflammation originates in the follicle.2
Hurley Stage I
Patient 2: Ultrasound shows a sinus tract2
A Chilean study sought to examine the morphological characteristics of HS using 3D ultrasound to visualize early anatomical changes in HS regions, which may allow the identification of lesions that may benefit from earlier medical treatment and possibly prevent the development of sinus tracts. In this study, ultrasound imaging demonstrated that one-third of patients classified by a certified dermatologist as Hurley Stage I (n=6) were shown to have subclinical sinus tracts.2
Ultrasound shows distortion of the hair follicle preceding perifollicular edema, suggesting that inflammation originates in the follicle.2
Hurley Stage II
Patient 3: Shows HS at a later stage2
Hurley Stage II
Patient 3: Ultrasound shows the formation of sinus tracts2
These lateral intrafollicular links and the involvement of the base of the hair follicles appear to be the initial steps in the formation of sinus tracts.2
Notice the predominant enlargement of the hair bulbs and the connection between the bulbs (right side of image). The dermis presents increased thickness (white vertical line) and there is a long sinus tract that connects the bottom of a hair follicle with the subcutaneous tissue.2
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Hurley Stage III
Patient 4: Ultrasound shows a large, subcutaneous fluid collection2
With more advanced disease, hair follicles are linked to fluid collections and sinus tracts spreading in a linear fashion to the subcutaneous tissue and enlarging to crypt-like structures with progressing disease.2
Notice the complete enlargement and connection of the base of the hair follicles (right half of the image).2
Hurley Stage I
Patient 1: Ultrasound shows dilation of hair follicles2
A Chilean study sought to examine the morphological characteristics of HS using 3D ultrasound to visualize early anatomical changes in HS regions, which may allow the identification of lesions that may benefit from earlier medical treatment and possibly prevent the development of sinus tracts. In this study, ultrasound imaging demonstrated that one-third of patients classified by a certified dermatologist as Hurley Stage I (n=6) were shown to have subclinical sinus tracts.2
Ultrasound shows distortion of the hair follicle preceding perifollicular edema, suggesting that inflammation originates in the follicle.2
Clinical Course of HS
Due to the progressive inflammatory nature of HS, it is proposed that a limited “window of opportunity” exists during which efforts to control HS activity may be most useful. The window may occur during early stages of disease—before the onset of sequelae and before the established disease causes irreversible damage.5
The use of therapeutic options during this window may alter the natural history of the disease by reducing tissue damage.5
*Changes in HS activity refer to changes in inflammatory activity or symptoms.
REFERENCES
1. Jemec GBE. Hidradenitis suppurativa. N Engl J Med. 2012;366(2):158-164. 2. Wortsman X, Jemec GBE. A 3D ultrasound study of sinus tract formation in hidradenitis suppurativa. Dermatol Online J. 2013;19(6). 3. Micheletti RG. Natural history, presentation, and diagnosis of hidradenitis suppurativa. Semin Cutan Med Surg. 2014;33(suppl 3):S51-S53. 4. Kimball AB, Sayed C, Duan Y, Longcore M, Crowley JJ. Characteristics associated with progression of hidradenitis suppurativa (HS): 2-year interim results from the HS UNITE registry. Poster presented at: American Academy of Dermatology Virtual Meeting Experience; June 12-14, 2020. 5. Martorell A, Caballero A, González Lama Y, et al. Management of patients with hidradenitis suppurativa. Actas Dermosifiliogr. 2016;107(suppl 2):32-42. 6. Lockwood SJ, Prens LM, Porter ML, Kimball AB. Treatment of hidradenitis suppurativa. In: Kimball AB, Jemec GBE, eds. Hidradenitis Suppurativa: A Disease Primer. Switzerland: Springer International Publishing AG; 2017:39-51.