Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic, inflammatory skin condition that develops deep below the skin surface. It is characterized by the recurrent formation of painful, deep-seated nodules and abscesses in areas where skin folds touch, such as the armpits, groin, and under the breasts. While pain is often the primary symptom, many individuals also experience intense itching (pruritus). This pruritus is a common complaint that significantly affects a patient’s quality of life.
The Presence and Frequency of Itching in HS
Itching is a frequent symptom for people living with HS. Studies indicate that pruritus affects a large percentage of patients, with prevalence rates ranging widely from roughly 35% to over 80% across different research cohorts. Although the pain associated with active lesions is typically more severe, persistent itch can become a troubling physical issue.
The itch is often described as intermittent or episodic, frequently co-presenting with sensations like stinging or burning. Pruritus is often reported to be worse during the evening or at night, contributing to poor sleep quality and distress. The most common locations for intense itching align with primary sites of HS activity, particularly the armpits and the buttocks.
Hallmark Symptoms of Hidradenitis Suppurativa
HS begins with the blockage of hair follicles in areas containing apocrine sweat glands. The disease progresses through the formation of painful, firm nodules deep beneath the skin. These lumps can enlarge and rupture, releasing a seropurulent discharge that often has an unpleasant odor.
A characteristic of advanced HS is the development of narrow channels beneath the skin called sinus tracts, which connect multiple lesions. Over time, repeated cycles of inflammation and healing lead to the formation of extensive scarring. These lesions most commonly affect the armpits, the groin, the inner thighs, and the skin folds under the breasts.
Underlying Causes of HS Related Pruritus
The itching experienced by HS patients is driven by the chronic inflammatory state of the disease. The process begins when the immune system reacts to ruptured hair follicles, triggering a cascade of inflammatory mediators. Mast cells, immune cells found in the skin, are present in higher numbers in both active HS lesions and surrounding skin.
These mast cells release histamine and inflammatory signaling molecules called cytokines that directly stimulate the nerve fibers responsible for sensing itch (pruriceptors). Chronic inflammation can also sensitize these nerves, contributing to a neuropathic component of the itch, especially in scarred areas. Additionally, HS often occurs in skin folds where heat, moisture, and friction are common. This environment can lead to maceration and secondary issues like fungal overgrowth, which further intensify the sensation of itching.
Strategies for Relieving the Itch
Managing pruritus involves reducing inflammation and soothing the skin.
Topical and Bathing Strategies
Topical relief can be achieved by applying cool compresses or ice packs to the affected areas, which calms irritated nerve endings. Applying mild, fragrance-free moisturizers or soothing agents like aloe vera gel helps maintain the skin barrier and reduce dryness that exacerbates itching. When bathing, use lukewarm water and gentle, antimicrobial cleansers free of harsh chemicals, dyes, or strong fragrances to minimize irritation.
Systemic Treatment
Systemic relief often includes the use of oral antihistamines, particularly sedating versions taken at night. These help disrupt the itch-scratch cycle and improve sleep quality. Ultimately, achieving long-term itch relief is tied to treating the underlying disease activity itself. Effective management of HS inflammation naturally reduces the biological triggers for pruritus.
Lifestyle Adjustments
Lifestyle adjustments are useful for minimizing flare-ups and subsequent itching. Patients should wear loose-fitting clothing to reduce friction against active lesions and minimize heat and sweating in the affected skin folds. Avoiding known triggers, such as excessive heat and physical activity that causes profuse sweating, can help prevent the skin irritation that often precedes an itchy episode.