Hidradenitis Suppurativa – Causes, Symptoms and Treatment

What is Hidradenitis Suppurativa?

Hidradenitis suppurativa (also known as acne inversa) is a chronic, inflammatory skin disease that primarily affects areas where skin rubs together or where sweat glands are abundant, such as the armpits, groin, buttocks, and beneath the breasts. The condition is characterized by recurring painful nodules, abscesses (pus-filled lumps), and tunnel-like tracts under the skin (sinus tracts) that often lead to permanent scarring. It typically begins after puberty and follows a relapsing-remitting course.

Causes and Risk Factors

The exact cause of hidradenitis suppurativa is not yet fully understood. It is considered a multifactorial disease involving several contributing factors:

• Follicular occlusion: The condition begins with a blockage of the hair follicles rather than the sweat glands themselves, as was previously believed. This blockage leads to inflammation and rupture.
• Genetic predisposition: A family history of the condition is present in approximately one third of cases, suggesting a hereditary component.
• Immune dysregulation: An overactive immune response and elevated levels of inflammatory cytokines play a central role in the development of the disease.
• Smoking: Tobacco use is one of the most significant risk factors and is associated with more severe disease.
• Obesity: A higher body mass index (BMI) promotes skin friction and sweating, both of which can worsen the condition.
• Hormonal influences: The disease is more common in women and may flare in relation to the menstrual cycle, suggesting a hormonal component.

Symptoms

The symptoms of hidradenitis suppurativa vary depending on the severity of the disease:

• Deep, painful nodules and lumps beneath the skin surface
• Abscesses that may rupture and drain pus or blood
• Sinus tracts -- tunnel-like connections between inflamed nodules under the skin
• Persistent itching, burning, and tenderness in affected areas
• Significant scarring following resolution of inflammatory episodes
• In severe cases: restricted mobility and considerable psychological distress

Hurley Staging System

The severity of hidradenitis suppurativa is commonly classified using the Hurley staging system:

• Stage I: Single or multiple abscesses without sinus tracts or significant scarring
• Stage II: Recurrent abscesses with sinus tract formation and scarring
• Stage III: Diffuse or widespread involvement with multiple interconnected tracts and extensive scarring

Diagnosis

Hidradenitis suppurativa is diagnosed clinically, based on physical examination and patient history. There are no specific blood tests or imaging studies that confirm the diagnosis alone. Key diagnostic criteria include:

• Characteristic location of lesions (armpits, groin, buttocks, under the breasts)
• Recurrent painful nodules or abscesses lasting at least six months
• Exclusion of other conditions such as boils, Crohn disease, or fungal infections

In cases where the extent of sinus tracts is unclear, skin ultrasound can be a useful tool for assessing subcutaneous involvement. Biopsies may occasionally be performed for differential diagnosis purposes.

Treatment

Treatment of hidradenitis suppurativa is tailored to disease severity and includes both medical and surgical approaches:

Medical Treatment

• Topical antibiotics: Clindamycin solution applied to the skin is used for mild forms of the disease.
• Systemic antibiotics: A combination of clindamycin and rifampicin taken orally for several months is used in moderate cases.
• Biologics: The TNF-alpha inhibitor adalimumab is the only biologic specifically approved for hidradenitis suppurativa. Additional biologics such as secukinumab are also used or are undergoing regulatory approval.
• Hormonal therapy: In women, oral contraceptives or antiandrogens may be beneficial.
• Retinoids: Acitretin may be used in selected cases.

Surgical Treatment

• Incision and drainage: Provides short-term relief for acute abscesses but does not prevent recurrence.
• Local excision: Surgical removal of individual affected areas.
• Wide local excision: For extensive Stage III disease, large areas of affected skin are surgically removed, offering the lowest recurrence rates.
• Laser therapy: CO2 laser or Nd:YAG laser may be used as complementary treatments.

General Lifestyle Measures

• Smoking cessation is strongly recommended
• Weight reduction in patients with obesity
• Wearing loose-fitting, breathable clothing
• Psychological support for patients experiencing significant emotional burden

Living with Hidradenitis Suppurativa

This condition can have a substantial impact on quality of life. Many patients experience chronic pain, embarrassment, and social withdrawal. Early diagnosis and consistent treatment are essential to prevent complications such as extensive scarring and functional limitations. Patient support groups and specialized dermatology centers can provide valuable resources and care.

References

1. Zouboulis CC et al. - European S1 guideline for the treatment of hidradenitis suppurativa/acne inversa. Journal of the European Academy of Dermatology and Venereology, 2015.
2. Jemec GB - Hidradenitis suppurativa. New England Journal of Medicine, 2012; 366(2):158-164.
3. Ingram JR - Hidradenitis suppurativa: pathogenesis, clinical features, and diagnosis. UpToDate, 2023.