Stubborn itching
Everyone experiences itchy skin at some point, but when the itch persists, it can become frustrating and overwhelming. Chronic itching, or pruritus, can significantly impact your quality of life. Severe itching can interfere with sleep, making it difficult to concentrate, and may lead to constant scratching, resulting in skin damage and even bleeding.
I can often predict when a patient is experiencing severe episodes of pruritus by observing the following signs: skin covered with abrasions and excoriations, with serum oozing from the affected areas; numerous scratches and red, inflamed spots; thick, rough skin with dark discoloration; and the formation of intense, generalized nodules, often affecting the limbs and body.
Even the eyes can provide clues: periorbital darkening, hollowed eyes, and folds in the lower eyelids; widespread hyperpigmentation across the face; dry, rough facial skin; and pallor around the lips are all indicators of stress and sleeplessness. These symptoms reflect the toll that chronic pruritus takes on the body and overall well-being.
Pruritus is an unpleasant sensation on the skin, eliciting the desire to scratch. Chronic pruritus (CP) refers to daily/almost daily itching, lasting more than six weeks. Clinically, pruritus has been described as the most frequent symptom in a dermatological condition. It has demonstrated a significant impact on patient’s quality of life that causes various problems related to sleep, anxiety, attention, and sexual function. In addition, many systemic diseases are also known to be associated with pruritus and further incapacitating nature of this condition. CP can arise from diseases of the skin such as psoriasis, atopic dermatitis, dry skin, scabies or urticaria. It can also result from disease of the organs of the body like the liver, kidney, blood, or from drugs. It may be neurological in nature, arising from disorders of the peripheral (part of your nervous system that lies outside your brain and spinal cord) and central nervous systems (brain and spinal cord); for instance, nerve damage, nerve compression, nerve irritation. Or chronic pruritus can be psychogenic, psychosomatic or mixed. In a worst-case scenario, it may be of undetermined (unknown) origin. There is also an increase in the prevalence of CP with advancing age. Moderate-to-severe pruritus is known to affect 60 percent of elderly individuals (65 years old).
Histamine is an incredible chemical that plays vital roles in our body, particularly in the immune response. It triggers swelling as part of the body’s healing process, and the sensation of itching is a natural reaction meant to help remove irritants from the skin. The itch-scratch cycle typically ends once the body has healed, which is part of our body’s amazing ability to sense and respond to external threats.
However, some forms of itching are caused by substances other than histamine, and we’ve only recently begun to understand these types of itch.
Scratching provides temporary relief by inducing pain in the skin, which interrupts the sensation of itch. This pain-relief mechanism is why scratching can feel so pleasurable. However, once you stop scratching, the itch often returns. The problem is that scratching or damaging the skin to alleviate itching can make the situation worse. Scratching can release histamine in the skin which, as one of the key hormones responsible for generating itch, only serves to make the itch more intense.
Why is so little attention paid to itch compared to pain?
Pain is so awful, and I would never say that there’s something ennobling about pain. But I think that there’s a certain amount of social respect given to people who are going through pain. But itching? It’s something that people suffer through alone and you kind of sound like a Disney character—you look like a dog with fleas, probably like Scooby Doo. And It’s embarrassing to scratch yourself in public. It’s inappropriate. I think people just kind of don’t take itch very seriously. I’ve also thought a lot about how, like, if you had a chronic itching support group, everybody would come into it and then just start scratching themselves, and then make everybody else itchier by being in the simple presence of people who are itchy.
Chronic pruritus is due to inflammation in approximately 60 percent of patients and may be caused by eczema, psoriasis, or seborrheic dermatitis. Approximately 15 percent of people with chronic pruritus have other causes including systemic diseases with secondary itch, such as uremic pruritus and cholestatic pruritus (bile flow obstruction), medication-induced pruritus such as pruritus due to immunotherapy, and infectious etiologies such as tinea corporis and scabies. A thorough history, review of symptoms, and laboratory evaluation should be performed, particularly for people with chronic pruritus lasting less than one year. Clinicians should consider the following tests: complete blood cell count, complete metabolic panel, and thyroid function testing to evaluate for hematologic malignancy, liver disease, kidney disease, or thyroid disease. First-line treatment for inflammatory chronic pruritus includes topical anti-inflammatory therapies.
However, approximately 10 percent of patients do not respond to topical therapies. In these patients, systemic oral or injectable treatments, such as dupilumab or methotrexate, may be considered.
When no underlying systemic disease associated with pruritus is identified, patients are likely to have neuropathic chronic pruritus or mixed etiology such as chronic pruritus of unknown origin. In these patients, neuropathic topical treatments, such as menthol, pramoxine, or lidocaine, can be used either alone or in combination with immunomodulatory agents such as topical steroids.
Other effective therapies for neuropathic pruritus include gabapentin, antidepressants such as sertraline or doxepin, or opioid receptor agonists/antagonists such as naltrexone or butorphanol.
