Management of Cast Itching
For cast-related itching, apply emollients and moisturizers to accessible skin around the cast edges, use cool air from a hair dryer or fan directed into the cast opening, and consider oral non-sedating antihistamines like loratadine 10 mg or fexofenadine 180 mg daily if itching is moderate to severe. 1
First-Line Non-Pharmacologic Interventions
Apply emollients at least once daily to all accessible skin around cast edges to prevent xerosis, which is a primary trigger for pruritus under casts 1
Direct cool air from a hair dryer (cool setting) or fan into the cast opening to provide symptomatic relief through counter-irritant effects 1
Keep the cast and surrounding skin as dry as possible after bathing or exposure to moisture, as dampness exacerbates itching 2
Avoid inserting any objects into the cast to scratch, as this can cause skin breakdown, infection, or damage to underlying healing tissues 2
Topical Treatments for Accessible Areas
Apply menthol 0.5% lotion or cream to skin at cast edges for counter-irritant relief, though this provides symptomatic rather than true antipruritic effects 1
Topical hydrocortisone 2.5% cream may be applied to accessible irritated skin at cast margins 3-4 times daily for up to 7 days maximum to address any inflammatory component 3, 4
Avoid topical capsaicin or calamine lotion, as these lack evidence for efficacy in managing pruritus 1
Systemic Pharmacologic Options
For Moderate Itching (Grade 2)
Start with non-sedating antihistamines as first-line systemic therapy: fexofenadine 180 mg daily, loratadine 10 mg daily, or cetirizine 10 mg daily 1
These agents are preferred over sedating antihistamines during daytime to avoid impairment of function 1
For Severe or Nocturnal Itching (Grade 3)
Consider sedating antihistamines at bedtime: diphenhydramine 25-50 mg or hydroxyzine 25-50 mg to break the itch-scratch cycle and improve sleep 3, 2
If antihistamines fail after 2 weeks, consider gabapentin 900-3600 mg daily in divided doses or pregabalin 25-150 mg daily as third-line neuropathic agents 3, 2
Critical Pitfalls to Avoid
Never apply topical corticosteroids under the cast or to inaccessible areas, as prolonged occlusion increases systemic absorption and risk of skin atrophy 1, 3
Do not use topical corticosteroids for more than 7 days even on accessible areas, as this increases risk of cutaneous atrophy and trauma 3, 4
Avoid topical doxepin for cast itching, as it requires limitation to 10% body surface area and carries contact dermatitis risk—impractical for cast management 1
Never insert coat hangers, knitting needles, or other objects into casts to scratch, as this can cause skin breakdown, introduce infection, or disrupt healing fractures 2
Reassessment Algorithm
Reassess after 2 weeks if no improvement or worsening occurs to advance to next treatment step 1, 2
If itching persists despite oral antihistamines, evaluate for secondary infection or contact dermatitis from cast materials, which may require cast change or padding adjustment 1
Consider cast removal or replacement if severe, uncontrolled itching persists, as this may indicate underlying skin complications requiring direct visualization 2