Topical Ketamine, Amitriptyline and Lidocaine (TKAL)
It can challenging to treat itching and burning - especially when no particularly underling cause can be found. The scalp dysesthesias are a group of conditions whereby patients have symptoms but no underlying pathology is clearly identifiable. In other words, there is no condition present such as a scarring alopecia or psoriasis that would account of the itch.
Altered nerve firing seems responsible for many scalp dysestheisas.
It seems that in many of these conditions associated with unexplained itching and burning there is an abnormal signal sent from nerve to the itch receptors that triggers itching. A variety of medications that are used in neurology can be used to block itching. For example, we commonly use a seizure medication gabapentin as well as an antidepressant amitriptyline. We've increasingly become interested in topical gabapentin to block nerve signals in patients with these so called scalp dysestheisas.
A recent study of 96 patients (68.8% female) with a mean age of 65 years looked at the benefit of a topical compounded product containing 10% ketamine, 5% amitriptyline, and 5% lidocaine compounded in a lipoderm cream. These patients in the study were troubled by itching for an average of 6 years and about one third had failed more than 3 previous treatments. Patients applied TKAL sparingly to areas that were the most severe, limiting to less than 30% of total body surface area up to 3 times daily. 63% of patients attributed relief directly to the use of TKAL. 58% had relief to a great extent and 14 35% to a moderate extent, experiencing itch relief within 4.18 ± 3.39 minutes on average. Side effects included burning in 7 % of patients, renders in 6 %, itching in 4 %. 1-2 % of patients had dizziness, numbness and a feeling of a raw scalp.
Side effects of TKAL
TKAL was very tolerated in this study. Side effects included burning in 7 % of patients, redness in 6 %, itching in 4 %. 1-2 % of patients had dizziness, numbness and a feeling of a raw scalp.
This is an interesting paper. TKAL was not used specifically in scalp dysesthesias but there it present a promising use as well - similar to how we currently use topical gabapentin. It's clear that for many drugs, topical treatments are safer than oral treatments and many patients are more receptive to starting a topical treatment. This treatment appears safe and well tolerated for the most part. The paper is freely available through the following link:
Topical ketamine-amitriptyline-lidocaine for chronic pruritus: A retrospective study assessing efficacy and tolerability. Journal American Academy Dermatology. April 2017. Volume 76, Issue 4, Pages 760–761
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887