[CUHK Medical Grand Rounds] A lady with multiple deep-seated boils and cysts
A 60-year-old lady was referred by a plastic surgeon for a long-standing history of facial acne, and painful lumps on the axillae and groin for over 25 years. She had hypertension, diabetes and obesity and was on medical therapy. There were no systemic symptoms. She was previously seen by GPs and was given antibiotics and topical antiseptics, with poor response. She also had surgical admissions for incision and drainage for infected epidermoid cysts. No definitive diagnosis was made over the years apart from “recurrent skin infections”. The patient was distressed by recurrent painful lumps with occasional foul-smelling discharge. She was finally referred to the dermatology clinic for assessment. Physical examination showed pitted scarring on the face, acanthosis nigricans and over 50 papulopustules on the back, axillae and inframammary areas. There were 10 nodules and cysts, three discharging sinuses and fistulation, and scarring over the neck, buttock, inner thighs and axillae. (Figure 1) A clinical diagnosis of hidradenitis suppurativa, Hurley stage II, was made. Wound swab for bacterial culture was negative.
Having failed to improve on 3 months of doxycycline, the patient was treated with oral isoretinoin 0.5 mg/kg. This resulted in moderate clinical improvement, with 50 percent reduction in inflammatory nodules and pustules. However, the patient suffered from diffuse alopecia, xerosis and cheilitis, and could not tolerate isotretinoin beyond 4 months of use. She was subsequently treated with adalimumab 40 mg weekly subcutaneously for 6 months after initial loading doses. The patient reported decrease in pain and discharge. Objectively, there was remarkable reduction of inflammatory papulopustules (from 50 to 5). (Figure 2) Discharge from sinus tracts dried up, although scars remained. The Dermatology Life Quality Index (DLQI) score dropped from 10 to 8 after treatment. Overall, there were no major untoward reactions except for three episodes of viral infections. Adalimumab was stopped after 6 months with a view to perform surgical excision of deep-seated tracts.
Hidradenitis suppurativa (HS), also known as acne inversa, is a suppurative scarring disease primarily affecting hair follicles with secondary apocrine gland involvement. The prevalence ranges from 0.035 to 4 percent1. HS predominantly affects females, with disease onset after puberty and diagnostic delay of years.1 The epidemiology of HS in Chinese is unknown, though nicastrin gene mutations have been identified.2 HS is often underdiagnosed, with patients presenting to various specialties.3
HS is a chronic condition characterized by recurrent, deep-seated inflammatory papulonodules, sterile abscesses and draining sinus tracts in the apocrine gland-bearing areas, such as the axillary, inguinal, anogenital and inframammary areas.4 Patients suffer from pain, malodorous discharge and recurrent infections. In late-stage disease, chronic ulceration, fistulation and disfiguring scars occur. It can then be complicated by squamous cell carcinoma and secondary amyloidosis.1,4 HS is mainly diagnosed clinically without specific diagnostic tests. Initial wound swab for bacteriology can be negative. However, the lesions can later be colonized by skin flora or other bacteria, leading to infections. Skin biopsy is seldom performed for diagnosis, but is useful to exclude alternative diagnoses or malignant transformation. Early HS histology shows keratin occlusion of hair follicles and perifollicular inflammation. Later, granulomatous inflammation, fibrosis, scarring of adjacent apocrine glands and sinus track formation are found. (Figure 3) Differential diagnoses include acne conglobata, carbuncles, multiple epidermoid cysts, pyoderma gangrenosum, fistulating deep fungal, mycobacterial or venereal infections, and fistulating Crohn’s disease. Excluding chronic infections and inflammatory bowel disease before diagnosing HS by tissue culture and histology is pertinent.
The severity of HS is graded by Hurley’s staging (single or few abscesses without scarring in stage I, formation of sinus tracts in stage II, and multiple interconnecting sinus tracts in stage III). General measures such as weight reduction, smoking cessation, and reduction of friction and moisture in intertriginous areas are important in all stages. Antiseptics, topical antibiotics and antiperspirants are frequently used to reduce symptoms of secondary infections. Prophylactic laser hair reduction can be considered.
Stage I HS (mild disease) can be treated with antibiotics (tetracycline group) and intralesional steroid for individual inflamed lesions. Stage II and above indicate severe disease, and treatment includes systemic retinoids, cyclosporine, or tumour necrosis factor-alpha antagonists.4 The strongest level of evidence for efficacy favours biologics (adalimumab weekly dosing, followed by infliximab), while evidence for other interventions is of lower quality or absent.5,6 Disabling scarring and sinus tracts can be managed by wide local excisions and secondary intention healing.7 Incision and drainage alone invariably causes relapse.7 Although surgical excision is the principal treatment for chronic, relapsing HS, it offers cure at the treated site only and does not reduce systemic inflammation. Hence, combined medical and surgical therapy is advocated for severe disease.
In conclusion, HS is a rare and disabling condition that masquerades as severe acne or folliculitis. A heightened index of suspicion is important for early disease recognition. Comprehensive treatment driven by dermatologists, regular long-term follow-up and timely communication with surgeons are crucial for treatment success.