Hidradenitis Suppurativa for the Dermatologic Hospitalist

Pearls for Inpatient and Emergency Evaluation and Management

Initial Evaluation
When dermatologic consultative services are asked to evaluate patients with HS, preliminary evaluation should reflect the acuity of the patient. Vital signs and toxicity should be reviewed to ensure that there is no evidence of severe infection necessitating critical or acute care.

History
History-taking should reflect assessment of the patient’s baseline disease, including date of initial onset; exacerbating factors, such as friction, smoking, pregnancy, and menses; and the current history of the patient’s flare. A history of antibiotics, immunosuppression, topical therapy, antiandrogen therapy, and vitamin A analog therapy also should be reviewed. If an initial diagnosis is made in the ED or inpatient setting, a family and personal history should focus on specific risk factors and disease associations, including inflammatory bowel disease,¹² pilonidal cysts,¹³ polycystic ovary syndrome,¹⁴ and metabolic syndrome.¹⁵

Physical Examination
As with all dermatologic consultations, a full-body skin examination, with special attention to the axilla, inframammary skin, groin, buttocks, and perineum, should be undertaken. In addition to these common areas of disease progression, examination should focus on atypical sites for disease manifestation, including the posterior auricular scalp, skin folds in the pannus and back, and the beard area in men. Evaluation of axillary and gluteal hair should note features of folliculitis and hair removal, which can exacerbate HS. Examination also should include an investigation of cutaneous manifestations of comorbid conditions, including acanthosis nigricans, contiguous or metastatic cutaneous Crohn disease, erythema nodosum, and pilonidal cysts. Caution should be exercised when diagnosing pilonidal cysts, as isolated or evolving HS in the gluteal cleft often is misdiagnosed as a pilonidal cyst.

Laboratory Evaluation
Testing often is misleading in patients with HS, especially in the acute setting, because the condition is a chronic inflammatory process. The C-reactive protein level as well as the absolute white blood cell and neutrophil counts often are elevated, even in the absence of acute infection.¹⁶ In fact, although patients often are treated with intravenous antibiotics by inpatient and emergency teams in the setting of these 3 laboratory abnormalities, these findings often reflect disease activity, not frank infection. Fever, especially low-grade fever, also can reflect ongoing disease activity. Thrombocytosis and anemia also are anecdotally common, though these findings have not been reported specifically in the literature.

Bacterial Cultures
The role of lesional and perilesional bacterial cultures is controversial in HS. Prior studies have demonstrated that biofilm formation may be associated with the chronic inflammation seen in HS.¹⁷ However, most data to date suggest that infection is not the primary driver of HS disease flares, as demonstrated by the frequency of sterile cultures and the variable response of the disease to penicillin and related antibiotics.¹⁸

Imaging
Ultrasonography and magnetic resonance imaging can be conducted if there is concern about deeper abscesses that are not apparent on examination. When interpreted by nondermatologic practitioners, however, the findings of these modalities can result in unnecessary surgical intervention, given the concern for development of infectious abscess.¹⁹

Diagnosis
Many patients with HS experience a notable delay in time to diagnosis, living with symptoms for 7 years on average prior to being given a name for their condition.²⁰ Often, patients seek ED care at initial presentation because lesions can present quickly and are associated with remarkable pain. Inpatient dermatologic evaluation can provide patients with definitive diagnosis, appropriate counseling that provides an overview of the natural history of the disease, lifestyle recommendations, and expedited connection to outpatient longitudinal care.

Diagnosis is made clinically by assessment for typical lesions, such as painful or tender papules, nodules, or abscesses in the axillae, inframammary region, groin, thighs, and perineal and perianal regions. Cordlike scarring often is seen in the absence of active inflammatory lesions.²¹ Double-headed open comedones and prominent follicular occlusion are seen in some phenotypes but are not required for diagnosis.²²

Multiple scoring modalities are in use²³; the Hurley staging system, initially developed for surgical staging, has become a commonly used method in the clinical setting²⁴:

• Hurley stage I: isolated nodules or abscesses;

• Hurley stage II: widely separate lesions and sinus tracts or scarring are suggestive; and

• Hurley stage III: multiple lesions with near-diffuse involvement and formation of sinus tracts and scarring.

Other scoring modalities, such as the Hidradenitis Suppurativa Clinical Response (HiSCR), are more commonly used in the clinical trial setting and quantitatively capture lesion count improvement while the patient is being treated.²⁵