Endocrine — A relationship has been proposed between sex hormones and HS. As an example, HS is seldom seen before puberty, and childhood cases have been associated with precocious puberty. However, pregnancy and menstruation do not have a consistent effect on the disease and new onset HS has been reported in postmenopausal women.

Hyperandrogenism has been suggested as a causal factor in womem based upon the following observations:

However, the association between androgens and HS remains controversial and may be due, in part, to obesity as many patients with HS are obese and SHBG is negatively correlated with body mass index A report on the endocrine status of 66 women with HS found no evidence of biochemical hyperandrogenism when compared to age-, weight- and hirsute-matched controls  Similar findings were noted in another study. Also arguing against a role for androgens in HS are the observations that, although acne is more prevalent and severe in males, HS is predominantly a female disease (13:5), and that HS has been treated effectively with testosterone in selected patients

HS has been associated with other endocrine disorders, such as diabetes, Cushing's disease, and acromegaly

  Genetic — There appears to be a familial predisposition to HS. In one report, a positive family history of HS was present more often in patients than controls matched for age and sex (26 versus 2 percent). Other studies examined 62 affected persons (40 females and 22 males) in 11 families. The authors suggested that HS has a genetic etiology in a pattern consistent with autosomal dominant inheritance.

  Other — HS has been associated with several cutaneous abnormalities, behaviors, and nonprescription drugs However, causality has not been proven.

PATHOLOGY — The histological findings of HS include

Unlike acne, significant sebaceous gland involvement is not a component of HS either by histologic examination or by measuring the sebum excretion rate

CLINICAL MANIFESTATIONS — The onset of HS is insidious with early symptoms consisting of pruritus, erythema, and local hyperhidrosis. Occlusion of a hair follicle results in a firm, pea-sized nodule or cyst, similar to the comedones of acne, that can rupture spontaneously and discharge purulent material. As the area heals, it becomes fibrotic and new nodules develop adjacent to the original lesions. Some lesions rupture spontaneously leading to sinus tract formation deep within the cutaneous tissue; others remain as indurated inflammatory masses. Hyperpigmentation, scars, and pitting are seen on the skin.

Women have mostly axillary and vulvar disease, while men are prone to perianal involvement. Single or multiple cutaneous sites can be affected. The disease may be mild and limited or severe, with new lesions continually developing and causing chronic, widespread, deep infection (show figure 1 and show figure 2).

Association with Crohn's disease — HS and anogenital Crohn's disease are similar in appearance and may be associated. Minor functional abnormalities of the gut mucosa or failure of gut IgA to inactivate bacterial or dietary antigens passing through the small intestine may result in the formation of IgA immune complexes; these complex may subsequently be deposited in the skin with resultant disease.

Association with malignancy — Squamous cell carcinoma arising in HS is rare, but has been reported in over 16 cases One-half of these patients died of widespread metastatic disease.

DIAGNOSIS — Early diagnosis of HS is essential since most cases can be effectively treated when diagnosed at an early stage. However, specific diagnostic criteria do not exist. Clinical criteria that suggest early HS include:

MEDICAL TREATMENT — Treatment of HS has been difficult and unsatisfactory in the past. Treatment now is directed at prevention of new lesions through medical management and elimination of existing lesions. Medical therapies, including antibiotics, antiandrogens, and retinoids, have better success in prevention or treatment of early isolated lesions; established sinus tracts and extensive lesions of advanced cases respond only to en bloc surgical excision. There are no data to recommend one medical treatment over another.

Antibiotics — Topical clindamycin (1 percent lotion twice per day for three months) is the only antibiotic that has been shown to be effective in a randomized placebo-controlled trial extending over a three month period. The number of abscesses, inflammatory nodules, and pustules was significantly better than placebo at each monthly evaluation. In another controlled trial, systemic therapy with tetracyclines (500 mg twice per day for three months) was as effective as topical clindamycin. Clindamycin also appears to prevent new lesions after existing disease has been cleared with isotretinoin and unroofing of sinus tracts.

Antibiotics may diminish odor and reduce pain, but there is no evidence that long-term antibiotic therapy alters the natural history of HS. Relapse is almost inevitable after withdrawal of medication.

Antiandrogens — Treatment with antiandrogens has produced mixed results in women with HS. A double-blind controlled, crossover trial comparing ethinyl estradiol (50 mcg) plus cyproterone acetate (50 mg) in a reverse sequential regimen with ethinyl estradiol (50 mcg) plus norgestrel (500 mcg) (Ovral®) showed that these treatments were equally effective. After 18 months, 7 of 18 patients were free of disease, 5 were improved, 4 were unchanged, and 2 worsened. Patients with infection secondary to extensive hidradenitis responded less well. Ethinyl estradiol/cyproterone acetate is not approved for use in the United States.

The author has successfully prevented recurrent groin and vulvar lesions in five women by discontinuing oral contraceptive pills with highly androgenic progestins in favor of ethinyl estradiol/drospirenone (Yasmin), combined with the antiandrogenic action of spironolactone 50 to 100 mg at bedtime.

Retinoids — Treatment with low dose isotretinoin (1 mg/kg orally for four months) at the earliest stages of HS has been used with varying results. As an example, in one trial of this therapy in 68 patients, the condition completely cleared during initial therapy in 16 cases and 11 maintained their improvement during the follow-up period. Treatment is most successful in the milder forms of HS, possibly by correcting the follicular abnormality that initiates the processes associated with chronic disease. The limited therapeutic effect of isotretinoin in HS may be due to the lack of significant sebaceous gland involvement.

Isotretinoin (2 mg/kg/day in divided doses) is also a useful adjunctive treatment to reduce inflammation before and after surgery, but is not effective against epithelial sinus tracts.

Corticosteroids — Intralesional corticosteroids have established benefit for patients with an isolated number of tender lesions, but are not appropriate for individuals with extensive disease. The lesion is injected with 5 to 10 mg triamcinolone acetate once monthly for one to three injections.

SURGICAL TREATMENT — The primary therapy of severe, extensive HS is surgical. Simple incision and drainage of individual nodules is helpful to bring short-term relief, but must be followed with active management. Otherwise, it is almost inevitable that recurrent episodes of inflammation will occur.

Unroofing — Sinus and fistulous tracts may be unroofed prior to more definitive surgery or as part of a multifaceted approach combining medical and surgical intervention. Under local or regional anesthesia, all tracts are mapped with a malleable metal probe and then opened with an electrocoagulation device and scissors. The entire roof of each tract should be completely removed, the tract curetted, and the epithelialized floor left exposed to heal by secondary intention. Marsupializing the wound may enhance its closure. However, there is a high incidence of recurrent disease (over 20 percent), often at a different anatomical site.

Local excision — Local excision with primary closure has a recurrence rate over 50 percent, but has a lower morbidity rate than wider ablative en bloc excision.

Combined medical-surgical treatment — For mild to moderate cases, combined therapies have shown promise in pilot studies. One such regimen consists of isotretinoin in high doses (2 mg/kg) for six months combined with surgical therapy: any sinus tracts are unroofed, debrided, and allowed to heal by granulation. After the course of isotretinoin is completed, topical clindamycin (2 percent lotion) is applied to prevent recurrent lesions. Spironolactone (25 mg daily) is then prescribed for its antiandrogen effect.

TREATMENT SUMMARY — I try to adhere to the following principles for the diagnosis and treatment of HS: