April 2017 | Case of the Month

The diagnosis is hidradenitis suppurativa.
 

Hidradenitis suppurativa (HS) is a chronic follicular occlusive disorder that affects the apocrine glands in the intertriginous axillary, groin, perianal, perineal, and inframammary skin. The clinical course is highly variable, ranging from relatively mild cases characterised by the recurrent appearance of papules, pustules, and a few inflammatory nodules to severe cases demonstrating deep fluctuant abscesses, draining sinuses, and severe band-like scars. Hidradenitis suppurativa affects about 1% of the population.

The exact cause of hidradenitis suppurativa remains unclear. What is understood is that the condition is a disorder of follicular occlusion, which begins with follicular plugging obstructing the apocrine gland ducts. Once the ducts are blocked the secretions cannot escape, the hair follicles swell causing rupture of the follicular epithelium leading to bacterial infection and formation of sinus tracts between abscesses under the skin.

Women are affected three times as often as men. HS is more common in black and Mediterranean people, and mainly arises between the ages of 20-40 years. Pain is a common feature.

Clinical findings

• Distribution
  • The extent and severity of the disorder varies widely between individuals
  • The axilla and groin are the most commonly affected sites. Under the breast is also a relatively common site. Anogenital involvement may include the mons pubis, vulva, sides of the scrotum, perineum, buttocks and perianal folds. Less commonly affected sites include the nape of the neck, waistband and inner thighs
     
• Morphology
  • Initially nodules develop, which may resolve spontaneously or rupture, discharging pus. At a later date new lesions recur in the adjacent area. If untreated, more numerous and larger lesions develop leading to the development of sinus tract formation
  • Scarring is common 

Management 

• The aim is to start treatment at an early stage - the longer it remains untreated the more severe the condition becomes and more difficult it is to treat
• Weight loss in obese patients is an essential part of management, smoking cessation may also help
• Topical antiseptics - Dermol 500 lotion ® can be used as a wash or applied and left on affected areas of skin. 4% chlorhexidine wash can also be used, however, this should be washed off after five minutes
• Systemic antibiotics - are the mainstay of treatment. Prolonged courses (several months to years) are used to reduce bacterial colonisation and inflammation:
  • One of the most useful antibiotics is lymecycline 408 mg (Tetrasyl ®), which has a strong anti-inflammatory affect in the skin. While the standard dose of lymecycline is one capsule a day on an empty stomach, some patients, especially if obese and / or have moderate-severe symptoms need to take one capsule twice a day - while such a dose is above that recommended, and should be discussed with the patient, it appears to be safe. Some patients may require long-term tetracycline treatment. Other antibiotics used include doxycycline, erythromycin / clarithromycin and metronidazole
  • Those not responding to the likes of lymecycline should be considered for the combination treatment of clindamycin 300 mg BD and rifampicin 300 mg BD for three months, which appears to be the most effective antibiotic regime. Rifampicin can very occasionally affect the liver and so it is recommended that patients should have their LFTs checked prior to treatment and within the first few weeks of starting treatment. Some patients require repeat / more prolonged courses of this treatment
• A super-potent topical steroid eg Dermovate cream, can be applied thinly BD on to new boils 
• Patients failing to respond to adequate treatment should be referred to Secondary Care for consideration of other treatments 

Please follow the link hidradenitis suppurativa for more information.