Erythrodermia is frequently accompanied by severe itching that is often resistant to treatment. In two cases, we found that low-dose treatment with ketamine hydrochloride was followed by a notable improvement of the pruritus symptoms.
A 58-year-old patient presented with chronic and persistent pruritus associated with idiopathic erythrodermia. Combination therapy with methotrexate and prednisolone was given for 4 months. Under this treatment, the patient developed herpes zoster infection in the left lateral segment (cervical vertebrae, C3 through C4), with subsequent extreme post-zoster neuralgia. Low-dosage intravenous ketamine hydrochloride therapy (single dose, 7.5 mg/d; weight, 58 kg) was therefore initiated. There was a clear reduction in pain, and the continuous severe itching also decreased. The patient had poor compliance. Consequently, the treatment could not be continued as oral therapy on an outpatient basis and it was also impossible to quantify the pruritus on a visual scale.
Fischer M, Steinborn A, Marsch WC. Therapy-Resistant Erythrodermia-Related Pruritus: Effective Treatment With Ketamine Hydrochloride. Arch Dermatol. 1999;135(10):1274-1275. doi:10-1001/pubs.Arch Dermatol.-ISSN-0003-987x-135-10-dlt1099