From the Guidelines
For a 39-year-old female experiencing pruritus on the chest and arms with sparse cherry angiomas and prediabetes, I recommend a two-pronged approach to manage the itching and investigate potential underlying causes. First, manage the itching with topical treatments like 1% hydrocortisone cream applied twice daily for 1-2 weeks, along with a non-sedating antihistamine such as cetirizine 10mg daily, as suggested by the British Association of Dermatologists' guidelines for the investigation and management of generalized pruritus in adults without an underlying dermatosis 1. For skin hydration, use fragrance-free moisturizers after bathing. Second, additional testing should include:
- Serum ferritin, iron studies, and vitamin B12 levels to rule out polycythemia vera or other myeloproliferative disorders that can cause both pruritus and cherry angiomas, as recommended by the British Association of Dermatologists' guidelines 1.
- Consider a skin biopsy of one of the angiomas if they are atypical or rapidly changing, as suggested by the guidelines for the investigation and management of generalized pruritus in adults without an underlying dermatosis 1. While cherry angiomas are typically benign vascular lesions that increase with age, their association with itching warrants investigation. The prediabetes should be addressed with lifestyle modifications including diet changes and regular exercise, as metabolic abnormalities can sometimes contribute to skin manifestations, according to the American Diabetes Association's standards of medical care in diabetes-2021 1. If itching persists beyond 4-6 weeks despite treatment, referral to dermatology for further evaluation would be appropriate. It is essential to note that the patient's normal thyroid, CBC, and liver function tests do not rule out other potential causes of pruritus, and further investigation is necessary to determine the underlying cause of the symptoms.
From the Research
Additional Testing Considerations
Given the patient's symptoms of pruritus on the chest and arms, with sparse skin lesions consistent with cherry angiomas, and normal thyroid labs, CBC, liver function tests, and a diagnosis of prediabetes (A1c), several factors should be considered for additional testing:
- The presence of cherry angiomas, which are benign vascular proliferations, may not directly relate to the patient's pruritus but could be a coincidental finding 2.
- The patient's pruritus could be related to various underlying conditions, including but not limited to dermatological, systemic, or neurological causes. Given the lack of response to antihistamines in some cases, other itch mediators and mechanisms should be considered 3.
- Topical antihistamines have mixed evidence for relieving pruritus, with stronger support for topical doxepin than for other agents like diphenhydramine 4.
- When considering additional testing, it's crucial to apply the principles of evidence-based medicine and shared decision-making, weighing the potential benefits and harms (physiological, psychological, and financial) of each test 5.
- A systematic approach to differential diagnosis, involving higher order thinking, is necessary to identify the underlying cause of the patient's pruritus from a set of possible competing diagnoses 6.
Potential Diagnostic Paths
- Further dermatological evaluation to rule out other skin conditions that could cause pruritus.
- Systemic evaluations, including but not limited to, gastrointestinal, renal, and hepatic assessments, given the potential for systemic diseases to cause pruritus.
- Neurological assessment if there's suspicion of neuropathic itch.
- Consideration of psychogenic pruritus if no other cause is found, given its inclusion in the differential diagnosis of generalized pruritus 3.