The inflammatory disease known as hidradenitis suppurativa (HS) affects areas of skin with apocrine or sebaceous glands. It typically presents after puberty and before age 40, in the areas under the breasts, within the axilla, along the inner thighs and around and within the groin and buttocks. The condition most commonly affects women. Luckily for patients and their OB/GYN practitioners, it is easily identified with ultrasound.
Signs and Symptoms of Hidradenitis Suppurativa
This painful, chronic skin disorder appears to develop from the occlusion and inflammation of hair follicles. It is characterized by painful nodules, pustules, abscesses, sinus tracts and fistulas, and can lead to keloids, contractures and even immobility.
There are three stages of HS:
- Abscess formation (solitary or multiple) that resembles acne.
- Recurring abscesses (solitary or multiple) with sinus tract formation, which may require incision and drainage.
- The development of multiple interconnected sinus tracts and abscesses, with fistula formation and scarring over a wide area of skin.
Improving Treatment With Ultrasound Identification
Currently, physicians primarily diagnose hidradenitis suppurativa through a hands-on clinical assessment. However, the use of ultrasound has been able to provide information on deeper subcutaneous tissue involvement.
Ultrasound reveals that the type and extension of HS involvement may be more severe than palpation alone can determine. The deep follicle inflammation visible on ultrasound suggests that the initial disease occurs from the base of the hair follicle, and spreads laterally through deeper tissues. Gaining a better understanding of the origin of the disease could lead to the development of more effective treatments.
In the meantime, studies have found ultrasound to be very helpful in identifying deeper nodules and sinus tracts that are not clinically palpable, but that cause significant symptoms in advanced cases. A case study published in Dermatologic Surgery illustrates how ultrasound can identify the borders and depth of an inflamed sinus tract for a planned surgical excision. Post-surgery, the study patient reported a significant improvement in symptoms.
Recurrence rates are as high as 34 percent among patients who have received radical surgical excision, according to a review published in Reviews in Endocrine and Metabolic Disorders. A thorough preoperative assessment for precise identification of the excision target is imperative for treatment success. Surgery can be a curative option, but only if it is complete and the surgeon is able to entirely remove the inflamed area.
Recognizing this, a proposal published by the American Society for Dermatologic Surgery reports that Dermatologic Ultrasound (DERMUS), a multinational group of physicians from nine countries, has been working to define a standard sonographic routine to evaluate staging and monitor progression in patients affected by HS. The benefits which ultrasound imaging provide, objective, timely and detailed evaluation, give clinicians information used to enhance therapeutic and treatment decisions.
Ultrasound Signs of Hidradenitis Suppurativa
Ultrasound can be used to identify features of both existing lesions and the predisposing features of skin thickness and hair follicles. Recognizable ultrasound features of HS include increased dermal thickness, more hypoechoic skin appearance and fluid collections in the subcutaneous layer.
A retrospective study published in Dermatologic Surgery analyzed ultrasound and clinical features of this disease to classify fistulas into four different types:
- Type A: Dermal fistula.
- Type B: Dermoepidermal fistula.
- Type C: Complex fistula.
- Type D: Subcutaneous fistula.
These classifications will significantly aid in guiding treatment methods. According to the study, types A and B were more amenable to medical therapy, but types C and D did not respond to medical treatment.
With ultrasound to assist in defining these lesions, clinicians will be better equipped to help patients through personalized medical and surgical management of HS.
Improving Patient Outcomes, Now and in the Future
Once established, HS is often difficult to treat. The inflammatory process of the skin, along with scarring, leads to an environment that facilitates the disease progression. A combination of hands-on clinical assessment plus high-resolution ultrasound of affected areas can lead to earlier detection by providing the most thorough information about the stage of the disease and its extent of involvement.
