Rare Cutaneous Sinus Paradox in Pure Neural Hansen’s Disease, Case Report Finds
A recent case report reveals a rare manifestation of pure neural Hansen’s disease, with discharging cutaneous sinuses despite the condition's classic definition strictly excluding primary skin lesions. The unique discovery highlights the unusual possibility of deep-seated neural abscesses tracking directly to the skin surface, which significantly complicates the traditional diagnostic framework for this chronic granulomatous infection.
These case report findings are published in the Indian Journal of Dermatology, Venereology and Leprology in April 2025 by Dr. Ritu Gujarati Vishwanath.
The specific case is of paramount importance to clinical practice because it proves that the absence of primary skin lesions in neural leprosy does not preclude the development of secondary cutaneous complications such as discharging sinuses. Recognizing these rare variants is absolutely vital for ensuring a timely diagnosis, which remains the primary factor in preventing irreversible nerve destruction and lifelong physical disability in young patients.
A 13-year-old boy presenting with four months of seropurulent discharge from his arm and hand weakness underwent investigations, including a Nerve Conduction Study (NCS) and High-Resolution Ultrasound (HRUS), which revealed a thickened ulnar nerve with hypoechoic tracts extending to the skin surface. These findings established a diagnosis of pure neural Hansen’s disease with a cutaneous sinus, and following a six-month paucibacillary multidrug therapy (MDT) regimen alongside physiotherapy and splinting, the patient’s claw hand improved, and the lesions successfully healed with scarring.
Mechanistic Insights
While clinicians occasionally observe nerve abscesses within the tuberculoid spectrum of leprosy, the progression of such an abscess into a direct sinus tract reaching the skin surface remains an exceedingly rare clinical event that warrants further study. This process involves the development of sub-acute, demyelinating neuritis that, depending on an individual's specific immune response, can lead to localized liquefaction, tissue necrosis, and the eventual formation of a cutaneous drainage pathway.
Potential Clinical Implementation
For healthcare practitioners, the case emphasizes the necessity of maintaining a high index of clinical suspicion and utilizing advanced imaging techniques to differentiate this condition from other ailments like ulnar nerve tuberculomas or nerve sheath tumors. Since India manages over half of the global burden of leprosy, any presentation involving unexplained muscle weakness and nerve enlargement must be evaluated with detail to ensure early intervention and the mitigation of long-term patient morbidity.
Reference
Vishwanath, R. G. formally presented these findings in a paper titled "An uncommon presentation of a common disease – Pure neural Hansen’s disease with sinus on skin," appearing in the Indian Journal of Dermatology, Venereology and Leprology in 2025, volume 91, pages S52 to S54, with the digital object identifier
