Unlike ordinary itching, neuropathic itch (NI) often arises from peripheral overstimulation or disruption of central itch inhibitory pathways. It is a chronic, pruritic, inflammatory skin disorder characterized by lichenification of the skin and paroxysmal intense itching, prone to recurrent episodes.
Fundamental Concepts of NI
NI possesses distinct transmission mechanisms (Figure 1) that differ from inflammatory pruritus (Table 1).
In intact skin, punctate stimuli (e.g., glass fiber) activating a few adjacent sensory fibers within the epidermis can induce itch without affecting neighboring fibers;simultaneous activation of these fibers induces pain;
Following peripheral sensory nerve injury (e.g., small fiber polyneuropathy, herpes zoster), a few abnormal epidermal nociceptors discharge spontaneous action potentials resembling intact skin firing patterns, mimicking the mechanism of focal activation causing neuropathic itch;
Degenerating peripheral nerves release inflammatory mediators like cathepsin S, which induce itching.
▼Figure 1: Mechanism of Itch Transmission in the Skin▼
▼Table 1: Differentiation Between Inflammatory and Neuropathic Itch▼
▲Images and text sourced from Yimaitong Neurology▲
Neuropathic itch is exclusively felt on skin and mucous membranes, often accompanied by inflammatory signs like edema and erythema. It typically occurs on easily accessible areas such as the neck, upper back, lateral elbows, lumbosacral region, ankles, and wrists.
However, scratching only intensifies the itching sensation. It may also cause papules or skin breaks, leading to progressively worse itching. This itchiness gradually forms a compulsive behavior where people feel an irresistible urge to scratch.Scratching causes papules to multiply, thicken, and merge. Vigorous scratching can damage and inflame the skin, leading to progressive thickening and the formation of lichenified, "old bark"-like patches.
Many neurodermatitis patients fall into this vicious cycle: more itching → more scratching → more damage → more itching. This requires serious attention.
To achieve effective treatment outcomes, beyond addressing local lesions and promoting skin repair, specific anti-itch medications are essential—such as the anti-itch product Shengxing Xingfushu. Suitable for all types of skin itching, including acute and chronic forms, it delivers multi-pronged relief.It offers multi-pronged relief by combating bacteria and parasites, reducing allergies and inflammation, detoxifying and reducing swelling, promoting lesion healing, and enhancing skin immunity. This comprehensive approach yields superior results compared to Western medicine's single-target treatments that merely eliminate pathogens or suppress itching.
Additionally, it is crucial to break the vicious cycle of itching, scratching, and skin damage. Patients require regular psychological and behavioral guidance, such as reducing spicy foods, increasing exercise, cultivating aesthetic interests, and especially avoiding consecutive nights of sleep deprivation.