Description

• Acute, tender, cystlike or nodular subcutaneous abscesses, commonly occurring in the skin of the axillae, perineum, areolae, and inframammary regions (rarely near umbilicus, scalp, trunk, or face)
• Chronic abscess formation with rupture and re-epithelialization causes sinus tracts to develop.
• Common from late puberty through age 40 years.
• System affected: Skin
• Synonym(s): Acne inversa; Verneuil's disease; Apocrinitis; Hidradenitis axillaris

Geriatric Considerations
Rare after menopause

Pediatric Considerations
Rarely occurs before puberty; occurrence in children associated with premature adrenarche

Pregnancy Considerations
No isotretinoin (Accutane) or tetracycline treatment during pregnancy. Disease may ease during pregnancy and rebound after parturition.

Epidemiology

• Predominant age of onset: 11–40 years
• Predominant sex: 3:1 female-to-male ratio

Incidence
Peak onset during 2nd and 3rd decades of life

Prevalence
0.3–4%

Risk Factors

• Obesity
• Smoking
• Hyperandrogenism
• Lithium may trigger onset, or exacerbate this condition.
• Androgenic progestins in oral contraceptive pills (OCPs) may trigger onset of this condition.

Genetics
Unknown; some studies suggest single gene transmission (autosomal-dominant), but the condition may also be polygenic.

General Prevention

• Weight loss if overweight or obese.
• Smoking cessation.
• Avoid constrictive clothing/synthetic fabrics, frictional trauma, heat exposure, excessive sweating, shaving, depilation, and deodorants.
• Use antiseptic soaps; apply tea tree oil topically.

Etiology

• Traditionally considered a disorder of apocrine glands, but now believed to be an inflammatory disorder of the hair follicle triggered by follicular plugging within apocrine gland–bearing skin.
• Lymphohistiocytic and granulomatous inflammation of the terminal hair follicle, sinus tract formation, and scarring
• Bacterial involvement is a secondary event.
• Sebum excretion is not an important factor.
• Smoking is a major factor in disease onset and severity.
• Considered part of follicular occlusive tetrad: Acne conglobata, dissecting cellulitis of scalp, hidradenitis suppurativa, and pilonidal cysts
• A genetic component may exist.

Commonly Associated Conditions

• Acne conglobata (not acne vulgaris)
• Perifolliculitis capitis abscedens et suffodiens (dissecting cellulitis of scalp)
• Pilonidal disease
• Arthritis and spondyloarthritis (seronegative)
• Obesity with associated diabetes mellitus, atopy, or acanthosis nigricans
• Irritable bowel disease (notably Crohn disease)
• Squamous cell carcinoma