Published Online: March 1, 2015
Itching is a common presenting symptom in the allergist/immunologist’s office because of allergic skin rashes such as eczema and chronic hives. However, in the patient where there is itching without a preceding rash, the list of possible causes are more numerous and include non-allergic conditions. In an article recently published in The Journal of Allergy and Clinical Immunology: In Practice, Drs. Gerald Lee and Cem Akin review approaches to treating patients with itching, but without rash.
First, the physician needs to determine whether the cause of itching originates in the skin or another organ system. Itching that is not caused by a skin condition usually does not have a rash, although some patients can develop a secondary rash that is usually symmetric and spares the difficult to reach mid-upper back. This rash can appear as dark nodules called prurigo nodularis, or thickened, leathery appearing skin called lichen simplex chronicus.
Itching without rash can be due to systemic, neurologic, or psychiatric conditions. Examples of systemic conditions include kidney disease, liver disease, hyperthyroidism, lymphoma, polycythemia vera, and HIV infection. Medications such as narcotics can have itching as a side effect. Nerve injury from shingles or spine disease can cause localized itching at the affected area. Finally, psychiatric conditions such as substance abuse or obsessive-compulsive disorder can also lead to itching.
The management of itching without rash should start with evaluating for and treating the underlying cause. Even if the cause of itching is unknown, a variety of therapies are available for symptomatic relief. Moisturizing the skin, keeping nails short, and wearing loose clothing can reduce the severity of itching. Although antihistamines are frequently used for itching, studies suggest that first generation antihistamines only help itching by causing sedation. The most successful oral medications are GABA analogues such as gabapentin, or antidepressants such as mirtazapine, which can be slowly increased to minimize side effects.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.