Hidradenitis Suppurativa: A Diagnostic Atlas provides a unique visual aid to the diagnosis of Hidradenitis Suppurativa (HS), also known as "acne inversa." The book covers the epidemiology and pathogenesis of the disease, its typical presentation, differences in manifestations of cutaneous versus systemic instances, and considerations for clinical and histopathological differential diagnosis. Guidance is also provided for the classification of disease severity and for managing the impact of HS on the patient's quality of life.
The book is packed with high-quality, full-color clinical images for each of the most common HS diagnostic imaging techniques, such as videodermatoscopy, ultrasound, computed tomography, and magnetic resonance imaging. As a clinical atlas, it helps dermatologists with differential diagnoses and correct assessments of disease severity, as well as possible complications of the condition. The book:
* Is highly focused on acne inversa, which can have a debilitating impact on quality of life
* Includes over 200 outstanding diagnostic clinical images
* Covers all imaging modalities used in the diagnosis and management of Hidradenitis Suppurativa
This book is a key resource for dermatologists, dermatopathologists, and dermatology nurses working with patients with HS.
Clinical features and diagnostic clues
Maria Letizia Musumeci,1 Maria Rita Nasca,1 Piera Catalfo,1 Karishma Bhatt,2 Federica Dall'Oglio,1 and Giuseppe Micali1
1Department of Dermatology, University of Catania, Italy
2University of Illinois at Chicago, Chicago, Illinois, USA
3.1 Cutaneous findings
Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent, debilitating, and complex skin disease affecting fully developed hair follicles located in apocrine gland-bearing body areas. Actually, it is considered as a primary follicular disease triggered by follicular occlusion, with subsequent inflammation and destruction of the skin appendage.
It clinically shows a wide spectrum of cutaneous lesions, often in different stages of evolution (Figures 3.1 to 3.4). In addition, different pattern of distribution and grades of severity (see Chapter 5) (Figures 3.5 to 3.9), as well as complications (Figures 3.10 and 3.11), extracutaneous features (arthritis, interstitial keratitis) and constitutional symptoms (fever, malaise), may occur . For these reasons, the clinical presentation may be extremely variable.
Figure 3.1. HS cutaneous lesions in different stages of evolution: highly inflamed, coalescent nodules along with cord-like scars (arrows) from previous flares on the left axilla
Figure 3.2. HS cutaneous lesions in different stages of evolution: highly inflamed, multiple draining nodules and abscesses on the left axilla. Multiple scars can be appreciated (arrow)
Figure 3.3. Same patient of Figure 3.2 in a resolution stage showing less inflammatory lesions
Figure 3.4.HS cutaneous lesions in different stages of evolution: multiple papules/pustules and draining nodules (yellow arrows) along with multiple small atrophic scars (red arrows)
Figure 3.5. HS presenting with multiple inflammatory nodules in the right axilla in a patient with bilateral involvement. HS severity grade: moderate
Figure 3.6. HS showing a single recurrent nodule on the left axilla in a patient with bilateral involvement. HS severity grade: mild
Figure 3.7. HS with multiple discharging nodules on inguinal folds along with postinflammatory hyperpigmentation and scarring from previous inflammatory episodes. HS severity grade: severe
Figure 3.8. HS presenting with inflammatory nodules and scarring on the right axilla in a patient with bilateral involvement. HS severity grade: severe
Figure 3.9. HS affecting the gluteal area with inflammatory discharging nodules and fibrotic tissue resulting from previous recurrent episodes. HS severity grade: severe
Figure 3.10. HS complications: vulvar lymphedema
Figure 3.11. HS complications: penile and scrotal lymphedema
3.1.1 Typical cutaneous lesions
They are divided into primary (nodules and abscesses), secondary (sinus tracts and drainage sinuses), and tertiary (double-ended pseudocomedones and scars) lesions. For such lesions a new nomenclature has recently been suggested , which is reported as footnotes in Table 3.1. Other HS lesions that may also occur are follicular papules/pustules and epidermal cysts. Most often, multiple typical cutaneous lesions are present simultaneously.
Table 3.1 HS cutaneous findings HS cutaneous lesions Typical Other Primary Secondary Tertiary
Nodulesa Sinus tractsb Double-ended pseudocomedonesd Follicular papules/pustules Abscessesa Drainage sinusesb Scars (hypertrophic scars/keloids, bridlec, rope/cord-like and atrophic scars) Epidermal cysts
aNodules with different depths.
dInterconnected keratin-filled multipores.
Lesion distribution and anatomical location are often suggestive of the disease. They usually occur in the intertriginous apocrine-gland-bearing areas of axillary, inguinal, perianal, perineal, mammary, and inframammary folds. Their localization pattern follows the "milk line" distribution of apocrine-related mammary tissue in mammals (Figure 3.12). Characteristically, the axillary and the inguino-crural areas are invariably affected and their bilateral involvement strongly suggests the diagnosis. Sometimes, lesions may extend laterally to the chest and/or to the breast (submammary, intermammary folds and areola). Other possible involved areas are the buttocks, pubis, waist, and scalp, including the nape, the periauricolar area, and the retroauricular fold [3, 4].
Figure 3.12 "Milk line": distribution of apocrine-related mammary tissue in mammals
In both sexes, the inguino-crural area is the most frequently affected. Interestingly, the perineal and perianal regions are more involved in men whereas the inner thighs, mons pubis, and labium major in women (Figure 3.13).
Figure 3.13. HS predilection areas in males and females
Primary lesions. HS begins with follicular occlusion, followed by inflammation and later by rupture of the pilosebaceous unit. Early lesions are solitary or multiple painful nodules of 0.5-2 cm diameter that may be superficial or deep ("blind boils") (Figures 3.14 to 3.16). They may have a different and unpredictable outcome: persist for weeks or months without any change, resolve spontaneously, or remain as "silent" nodules with inflammatory recurrences. When deeply located in the hypodermis, nodules may sometimes be barely appreciable. Twelve to 48 hours before an overt inflammatory nodule occurs, half of patients report prodromal symptoms, including burning, stinging, pain, pruritus, warmth, and/or hyperhidrosis. The mean duration of a single inflammatory nodule is generally 7-15 days. They may be extremely painful. In severe cases, evolution toward abscesses and external rupture may be observed. Recurrence may lead to chronic secondary lesions, with intermittent release of serous, purulent, or bloodstained discharge. Foul smelling from bacterial colonization is common. The inflammatory events may persist for months, and sometimes for years. Abscesses ultimately heal, evolving into tertiary lesions, producing fibrosis, dermal contractures, induration, and scarring [2, 5].
Figure 3.14. Typical primary lesion: solitary axillary inflammatory nodule
Figure 3.15. Typical primary lesion: solitary axillary abscess
Figure 3.16. Typical primary lesions: multiple axillary nodules, some of them eroded
Secondary lesions. Secondary lesions are sinus tracts and drainage sinuses (Figures 3.17 to 3.19) [2, 5]. Each sinus tract has a variable length and shape and shows two openings (drainage sinuses): the inner that may extend deep to the underlying fascia and muscles, and the outer one opening at the skin surface, where a fluid discharge may occur. Typically, they may persist for months or even years and, quite frequently, they are colonized by gram-negative and anaerobic bacteria that create foul smelling. Sinus tracts have a linear or angular shape and are not always palpable. They are initially single, but may later split, resulting in multiple interconnected drainage sinuses. Sometimes, extensive sinus networks can extend into deeper tissues, including muscle, fascia, lymph nodes, and other structures (i.e., urethra or rectum), depending on the anatomic site. As a result of chronic inflammation and disruption, pyogenic granulomas (Figure 3.20) and ulceration (Figure 3.21) may develop. Chronic inflammation in the same site is the cause of fibrosis in the surrounding skin (Figures 3.22 to 3.24).
Figure 3.17. Typical secondary lesions: single infiltrated plaque of the buttock with multiple draining sinuses, some of them showing purulent discharge
Figure 3.18. Typical secondary lesions: multiple plaques of the inguinal fold showing dry draining sinuses (red arrow) along with discharge draining ones (yellow arrows)
Figure 3.19. Typical secondary lesions: sero-purulent discharge from a draining sinus on the buttock
Figure 3.20. Outcome of chronic inflammation: pyogenic granulomas developing on scarring area
Figure 3.21. Outcome of chronic inflammation: ulcerative nodules showing granulation tissue
Figure 3.22. Outcome of chronic inflammation: fibrotic plaques localized in the inguinal folds
Figure 3.23. Outcome of chronic inflammation: fibrosis of the scrotum
Tertiary lesions. Tertiary lesions include double-ended pseudocomedones (Figure 3.25) and scars...