From the Guidelines

Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent, debilitating skin follicular disease.

HS is characterized by painful deep-seated, inflamed lesions in the apocrine gland-bearing areas of the body, most commonly in the axillary, inguinal, and anogenital regions 1.
The condition may present with comedones, papules, pustules, nodules, cysts, abscesses, sinus tracts, and fistulae in flexural areas, with significant phenotypic variation among patients 1.
HS can cause severe pain, pruritus, chronic discharge, and a persistent malodour, leading to significant patient morbidity 1.

Consensus diagnostic criteria require typical lesions in typical sites, with the disease being chronic and recurrent 1.
Baseline disease severity is often measured using the Hurley staging system 1.

HS is a debilitating disease that can result in fibrosis, dermal contractures, scarring, and a consequent reduction in mobility 1.
The disease can have a moderate to severe impact on quality of life, as demonstrated by an average Dermatology Life Quality Index (DLQI) score of 18 1.
HS can be associated with complications such as fistula formation, lymphoedema, anaemia, and the development of squamous cell carcinoma 1.

From the Research

Hidradenitis suppurativa (HS) is a non-contagious chronic inflammatory and often debilitating skin disease characterized by recurrent painful nodules, draining sinus tracts, and abscesses 2, 3, 4, 5, 6.
The disease primarily affects the axillary, perineal, inguinal, intermammary, and inframammary regions 2.
HS is also known as acne inversa 4, 6.

The estimated global prevalence rate of HS is up to 4% 2, although other studies report a prevalence of 1-2% 3, 4, 6.
HS typically starts in early adulthood 4.
The prevalence of HS may be under-reported due to variance in data collection methods, ethnicity, geographical location, and under-diagnosis 6.

The etiology of HS is still unknown, but it is now considered a disease of follicular occlusion 2.
HS involves activation of cells of the innate and adaptive immune systems, with pivotal roles for pro-inflammatory cytokines such as tumour necrosis factor, IL-1β, and IL-17 4, 6.
The clinical presentation of HS includes painful nodules, abscesses, and pus-discharging tunnels commonly affecting the axillary, anogenital, inguinal, and perianal/gluteal areas 6.

The diagnosis of HS is made clinically and is based on typical lesions, location, and chronicity 2.
Diagnostic delays are evident due to early lesions of HS mimicking other skin conditions 2, 3, 6.
Treatment options for HS include antibiotic treatment, neutralization of tumour necrosis factor, and surgical intervention, as well as lifestyle modification 4, 6.
The anti-TNF-α antibody adalimumab is currently the only biologic approved for HS, although its efficacy varies 6.