What is the appropriate treatment for itchy scalp papules in an otherwise healthy adult?

Treatment of Itchy Bumps on the Scalp

Start with liberal emollient application to the scalp after every wash, combined with a 2-4 week trial of moderate-potency topical corticosteroid (clobetasone butyrate once daily), while systematically ruling out infectious causes like tinea capitis or scabies that require specific antimicrobial therapy. 1

Initial Diagnostic Considerations

Before initiating symptomatic treatment, you must exclude specific treatable causes:

• Check for tinea capitis: Look for patterns like black dot hair stubs, grey patches, or inflammatory boggy masses (kerion). Use dermoscopy to identify comma-shaped or corkscrew hairs, and collect specimens (scalp scraping, plucked hairs) for mycological confirmation before starting treatment. 2 If confirmed, oral antifungals (griseofulvin for Microsporum, terbinafine for Trichophyton) are required—topical therapy alone will not cure tinea capitis. 2

• Evaluate for scabies: Examine for burrows, particularly in web spaces and wrists. In infants and elderly patients, scabies commonly affects the scalp, hairline, neck, and temple (unlike adults where scalp involvement is rare). 3 If scabies is confirmed, apply permethrin 5% cream from head to soles, leave for 8-14 hours, then wash off—one application is generally curative. 3

• Review medications: Specifically ask about opioids, chloroquine, or recently started drugs that commonly cause pruritus. 1

First-Line Topical Treatment Algorithm

For non-infectious scalp pruritus with papules:

• Emollients with high lipid content: Apply liberally and frequently, especially after washing, to restore the skin barrier and provide a surface lipid film that retards water loss. 4, 1 This is the foundation of all pruritus management. 4

• Topical corticosteroid: Use clobetasone butyrate (moderate potency) once daily to affected areas for 2-4 weeks. 1 This addresses inflammation rapidly. 5 Critical pitfall: Avoid prolonged use beyond 4 weeks without breaks, as this causes scalp atrophy and rebound symptoms. 1

• Topical menthol preparations: May provide additional symptomatic relief through cooling effects. 1

• Avoid these topicals: Do not use crotamiton cream (British Journal of Dermatology Strength B recommendation against), topical capsaicin, or calamine lotion—these lack efficacy for scalp pruritus. 4

Second-Line Systemic Options

If topical therapy fails after 4 weeks of optimized use:

• Non-sedating antihistamines: Start fexofenadine 180mg daily or loratadine 10mg daily as preferred agents. 4, 1 Alternatively, use mildly sedating cetirizine 10mg daily. 1

• Enhanced antihistamine blockade: Consider combining H1 + H2 antagonists (fexofenadine plus cimetidine) for additive benefit. 4, 1

• Absolutely avoid sedating antihistamines (like hydroxyzine) for long-term use due to dementia risk, particularly in elderly patients (British Journal of Dermatology Strength C recommendation against). 4, 1

Third-Line Options for Refractory Cases

When first and second-line therapies fail:

• Gabapentin or pregabalin: Consider if there's a suspected neuropathic component (check for localized sensory changes or dermatomal distribution). 1 Gabapentin may be particularly beneficial in elderly patients. 6

• Antidepressants: SSRIs (paroxetine, fluvoxamine) or mirtazapine may help when neuropathic mechanisms or psychological overlay is suspected. 1

• Phototherapy: Narrowband UVB is a British Journal of Dermatology Strength A recommendation for refractory pruritus and requires dermatology referral. 4, 1

When to Refer to Dermatology

Refer if:

• No response to optimized topical therapy after 4 weeks 1
• Diagnostic uncertainty about whether a subtle dermatosis (like early psoriasis or contact dermatitis) is present 1
• Need for phototherapy or systemic immunomodulators 1

Special Considerations for Elderly Patients

If the patient is over 65 years:

• Mandatory 2-week trial: Use emollients plus topical steroids first to exclude asteatotic eczema (extremely common in elderly). 6, 4
• Prefer high lipid content moisturizers for this age group. 6, 4
• Never use sedating antihistamines in elderly patients due to dementia risk. 6, 4

Common Pitfalls

• Persistent itch after treatment doesn't always mean failure: Patients may experience pruritus for up to 14 days after successful treatment of conditions like scabies—this is not an indication for retreatment unless living mites are demonstrated. 3
• Don't stop antifungal treatment based on clinical improvement alone: For tinea capitis, continue until mycological clearance is documented. 2
• Don't overlook medication review: Drug-induced pruritus is frequently missed and easily reversible. 1