Herpes zoster and pruritus

Pruritus: Progress toward Pathogenesis and Treatment

Pruritus, the most common cutaneous symptom, is widely seen in many skin complaints. It is an uncomfortable feeling on the skin and sometimes impairs patients' quality of life. At present, the specific mechanism of pruritus still remains unclear. Antihistamines, which are usually used to relieve pruritus, ineffectively work in some patients with itching. Recent evidence has suggested that, apart from histamine, many mediators and signaling pathways are involved in the pathogenesis of pruritus. Various therapeutic options for itching correspondingly have been developed. In this review, we summarize the updated pathogenesis and therapeutic strategies for pruritus.

Thiamine, cobalamin, locally injected alone or combination for herpetic itching: a single-center randomized controlled trial

OBJECTIVES

The present study was designed to explore the efficacy of locally injected thiamine or cobalamin in relieving itch or pain and improving the daily living activities among patients with herpetic itching.

METHODS

Eighty eligible patients with herpetic itching with a worst itching score of ≥ 4 were randomized to receive locally injected thiamine (B1 group), cobalamin (B12 group), lidocaine (LD group), or combination of thiamine and cobalamin (COB group) for 4 weeks. The treatment efficacy was assessed based on the patients' pruritus and pain severity, global impression of change, and activities of daily living and quality of life.

RESULTS

After 7 days, thiamine yielded a significant itch relief, cobalamin yielded a significant pain relief, and their combination significantly relieved both pain and itch; which all continued till the endpoint (all Ps<0.001). However, lidocaine did not provide significant itch or pain relief than the other groups. Sixteen patients in the thiamine group achieved ≥ 30% itch reduction; 18 patients in the cobalamin group obtained ≥ 30% pain reduction; and 18 patients achieved ≥ 30% itch reduction and 19 patients obtained ≥ 30% pain reduction in the combination group. The activities of daily living and quality of life data at the endpoint were consistent with a significant benefit in the thiamine (P<0.05), cobalamin, and combination groups (both Ps<0.001).

DISCUSSION

Locally injected thiamine had a significant antipruritic effect, cobalamin had an analgesic effect, and their combination had the dual effect with no obvious synergies. This intervention was efficacious, tolerable, and safe for herpetic itching.