Boil
Follicular pyodermas (carbuncles, furuncles, boils)7-9

Differentiation: Unlike HS, which typically exhibits a chronic and recurrent course, follicular pyodermas are transient lesions that usually respond rapidly to appropriate antibiotic therapy. In addition, the follicular pyodermas do not cause the comedones, persistent sinus tracts, and hypertrophic scarring observed in HS.
Cutaneous Crohn’s disease7,10

Cutaneous Crohn's disease
Adapted with permission from Rice SA, Woo PN, El-Omar E, et al. BMC Res Notes. 2013.10
This work is licensed under a Creative Commons Attribution 4.0 International License.
Differentiation: “Knife-cut” ulcers and no blackheads; fistulas connect with the gastrointestinal tract; concurrent with gastrointestinal Crohn’s disease.
Acne, cystic acne7

Cystic acne
Differentiation: Distribution on the face, back, and upper chest, and include whiteheads. HS primarily involves the axillae, groin, buttocks, and inframammary folds. Additionally, HS typically involves more deep-seated lesions leading to sinus tracts and scarring.
Granuloma inguinale7

Granuloma inguinale
Differentiation: Red ulcers that bleed easily, granulation of tissue; has Donovan bodies (histology); infectious agent: Klebsiella granulomatis.
Lymphogranuloma venereum7

Lymphogranuloma venereum
Differentiation: Bacterial etiology: Chlamydia trachomatis (serotype L1-L3)
Review the following 3 patient cases and determine the most likely diagnosis. Reference the HS diagnosis criteria to help inform your choices.
“It’s critically important to diagnose HS early and intervene with medical therapies given the progressive, irreversible nature of the disease.”
- Dermatologist
REFERENCES
1. Micheletti RG. Natural history, presentation, and diagnosis of hidradenitis suppurativa. Semin Cutan Med Surg. 2014;33(suppl 3):S51-S53. 2. Jemec GBE. Hidradenitis suppurativa. N Engl J Med. 2012;366(2):158-164. 3. Kimball AB, Rahawi K, Duan Y, Alavi A, Okun MM. Impact of delayed diagnosis in patients with hidradenitis suppurativa (HS): real-world data from the UNITE HS registry. Poster presented at: Symposium on Hidradenitis Suppurativa Advances; November 1-3, 2019; Detroit, MI. 4. Garg A, Neuren E, Cha D, et al. Evaluating patients' unmet needs in hidradenitis suppurativa: results from the Global Survey Of Impact and Healthcare Needs (VOICE) Project. J Am Acad Dermatol. 2020;82(2):366-376. 5. Alavi A, Lynde C, Alhusayen R, et al. Approach to the management of patients with hidradenitis suppurativa: a consensus document. J Cutan Med Surg. 2017;21(6):513-524. 6. Saunte DM, Boer J, Stratigos A, et al. Diagnostic delay in hidradenitis suppurativa is a global problem. Br J Dermatol. 2015;173(6):1546-1549. 7. Saunte DML, Jemec GBE. Hidradenitis suppurativa: advances in diagnosis and treatment. JAMA. 2017;318(20):2019-2032. 8. Boils and carbuncles. Mayo Clinic. Updated September 11, 2019. Accessed January 29, 2020. https://www.mayoclinic.org/diseases-conditions/boils-and-carbuncles/symptoms-causes/syc-20353770. 9. Collier F, Smith RC, Morton CA. Diagnosis and management of hidradenitis suppurativa. BMJ. 2013;346:f2121. 10. Rice SA, Woo PN, El-Omar E, Keenan RA, Ormerod AD. Topical tacrolimus 0.1% ointment for treatment of cutaneous Crohn's disease. BMC Res Notes. 2013;6:19. 11. Shah N. Hidradenitis suppurativa: a treatment challenge. Am Fam Physician. 2005;72(8):1547-1552. 12. Dermnet Skin Disease Atlas. Accessed June 18, 2019. http://www.dermnet.com/images/Epidermal-Cyst/picture/16454.