Common Scalp Skin Lesions and Management
The scalp's unique environment—high follicular density, abundant sebum production, and warm, dark conditions—makes it particularly susceptible to specific dermatologic conditions that differ from other body sites 1, 2.
Most Common Scalp Lesions
Infectious/Inflammatory Conditions
1. Tinea Capitis (Scalp Ringworm)
This fungal infection of scalp hair follicles and surrounding skin is the most important infectious scalp condition, particularly in children 3.
Clinical Presentations:
- Grey patch: Fine scaling with patchy circular alopecia, dull grey appearance (typically Microsporum species)
- Black dot: Patches of alopecia with fine scale and broken-off hair stubs appearing as "black dots" (typically Trichophyton species like T. tonsurans, T. violaceum)
- Diffuse scale: Generalized scaling resembling dandruff with minimal alopecia
- Kerion: Painful, boggy, inflammatory mass with pustules, matted crust, and regional lymphadenopathy—often misdiagnosed as bacterial abscess 3
- Favus: Chronic inflammatory variant with yellow, cup-shaped crusted lesions (scutula), seen with T. schoenleinii 3
Diagnosis:
- Sample via scalp scraping, hair pluck, brush, or swab for microscopy and culture 3
- Start treatment empirically if cardinal signs present (scale, lymphadenopathy, alopecia, or kerion) while awaiting mycology 3
Management Algorithm:
Topical therapy alone is inadequate—oral therapy is required 3
Choice depends on causative organism:
Treatment failure: Consider compliance, reinfection, or switch to second-line (itraconazole) 3
2. Seborrheic Dermatitis/Dandruff
These represent a spectrum from mild (dandruff) to severe (seborrheic dermatitis), characterized by erythematous patches with yellow, oily scales 4, 5.
Key Features:
- Symmetric, poorly defined erythematous patches with yellow scales
- In darker skin, erythema may be subtle with hypopigmentation as presenting sign 4
- Associated with Malassezia species overgrowth 5
Management:
- Scalp: Antifungal shampoos (ketoconazole, selenium sulfide, zinc pyrithione) or topical corticosteroid solutions/foams 4
- Thick scale: Keratolytic agents (salicylic acid 5-10%) 6, 4
- Face/body: Antifungal creams, topical corticosteroids, or calcineurin inhibitors 4
3. Scalp Psoriasis
Sharply demarcated erythematous plaques with thick, silver-white scaling affecting approximately 2% of the population 6.
Distinguishing Features:
- Well-demarcated borders (unlike seborrheic dermatitis)
- Thicker, silvery scale
- Often extends beyond hairline
- Associated with nail changes and body psoriasis
Management:
- First-line: Topical corticosteroids (most rapid effect, 3-4 weeks to maximal efficacy) 6
- Alternatives: Vitamin D3 analogues (calcipotriol), coal tar preparations, salicylic acid for descaling 6
- Adjunctive: Imidazole antifungals may help when Pityrosporum overgrowth present 6
- Severe/recalcitrant: Systemic therapy (methotrexate, cyclosporine, acitretin) 6
4. Alopecia Areata
Autoimmune-mediated patchy hair loss without scarring 7.
Clinical Features:
- Smooth, round patches of complete hair loss
- "Exclamation mark" hairs at margins (short, broken hairs wider at distal end)
- Dermoscopy shows yellow dots, dystrophic hairs 7
- 20% have family history 7
Differential Diagnosis Pitfalls:
- Trichotillomania: Incomplete hair loss, firmly anchored broken hairs in anagen phase 7
- Tinea capitis: Scalp inflammation present (may be subtle) 7
- Early scarring alopecia: Requires biopsy if uncertain 7
Management:
- Critical principle: Avoid hazardous treatments given no direct health impact and potential for spontaneous regrowth 7
- Focus on psychological support and self-acceptance
- Investigations generally unnecessary unless diagnosis uncertain 7
5. Pediculosis Capitis (Head Lice)
Parasitic infestation causing pruritus and visible nits on hair shafts 1, 2.
6. Scalp Rosacea (Red Scalp Disease)
Underrecognized inflammatory condition with diffuse erythema, dry scaling, and inflammatory papules/pustules 8.
Features:
- Predominantly affects middle-aged men
- Associated with androgenetic alopecia
- Trichoscopy shows characteristic vascular patterns
- Non-scarring condition with favorable prognosis 8
Management:
- Oral tetracyclines as first-line (extrapolated from facial rosacea) 8
Critical Diagnostic Approach
When evaluating scaly scalp lesions, systematically assess:
- Pattern of hair loss: Patchy vs. diffuse, complete vs. incomplete
- Scale characteristics: Fine vs. thick, white vs. yellow, adherent vs. loose
- Border definition: Sharp (psoriasis) vs. poorly defined (seborrheic dermatitis)
- Inflammation: Minimal vs. boggy/pustular
- Hair shaft examination: Black dots, exclamation marks, broken hairs
- Distribution: Localized vs. generalized
- Associated findings: Lymphadenopathy, body lesions, nail changes
Dermoscopy aids diagnosis by revealing specific patterns (yellow dots in alopecia areata, vascular changes in rosacea, comma-shaped hairs in tinea) 3, 7, 8.
Common Pitfalls to Avoid
- Mistaking kerion for bacterial abscess—this delays appropriate antifungal therapy 3
- Using topical therapy alone for tinea capitis—oral treatment is mandatory 3
- Wrong antifungal choice—terbinafine fails for Microsporum, griseofulvin less effective for Trichophyton 3
- Confusing trichotillomania with alopecia areata—look for incomplete loss and firmly anchored hairs 7
- Overlooking scalp rosacea—frequently misdiagnosed due to clinical overlap with other conditions 8