What is the diagnosis and treatment for a 21-year-old male with a 3-day history of inflamed, erythematous, and itchy skin around the right lateral neck and posterior upper chest, which started after playing basketball and traveling, with no past medical history of asthma, diabetes, or skin cancer, and who is currently hemodynamically stable and afebrile?

Diagnosis: Irritant Contact Dermatitis (Frictional Dermatitis)

This is irritant contact dermatitis caused by mechanical friction and sweating during basketball, not an allergic reaction, infection, or chronic inflammatory condition. 1, 2, 3

Clinical Reasoning

The presentation strongly indicates frictional/irritant contact dermatitis based on:

• Acute onset (3 days) immediately after physical activity (basketball) in a previously healthy young adult 2, 3
• Unilateral distribution (right lateral neck and posterior upper chest) corresponding to repetitive contact areas during sports activity 4
• Erythematous, inflamed, itchy skin without vesicles, weeping, or crusting, ruling out acute allergic contact dermatitis or infection 4
• Worsens with manipulation/scratching, typical of irritant dermatitis 5
• No systemic symptoms (afebrile, hemodynamically stable, no respiratory symptoms) 4
• Temporal relationship to travel and new activity, not new products or fabrics 4

The right-sided neck and upper chest distribution suggests friction from clothing, equipment straps, or repetitive arm movements during basketball combined with sweat accumulation creating an irritant microenvironment 1, 3.

Differential Diagnoses to Exclude

• Allergic contact dermatitis: Would typically show vesicles, more defined borders, and bilateral distribution if from clothing/detergent 6, 4
• Tinea corporis: Would show advancing scaly border with central clearing, not acute erythema 6
• Bacterial infection (impetigo): Would show honey-crusted lesions, weeping, or pustules—absent here 6
• Atopic dermatitis flare: Patient has no history of atopy, asthma, or chronic eczema 6
• Seborrheic dermatitis: Would show greasy yellowish scales in seborrheic distribution (scalp, face, chest midline), not unilateral acute erythema 5

Treatment Protocol

Immediate Management (First 7-10 Days)

Primary anti-inflammatory therapy:

• Hydrocortisone 1% cream applied to affected areas 3-4 times daily for 7-10 days 7, 4
• This is the appropriate potency for neck/chest areas where skin atrophy risk is moderate 6, 5
• Continue for full 7 days even if symptoms improve sooner 8

Essential supportive care:

• Use mild, pH-neutral (pH 5) non-soap cleansers or dispersible creams as soap substitutes to preserve natural skin lipids 6, 5
• Apply fragrance-free emollients (petrolatum or mineral oil-based) immediately after bathing to damp skin to create a protective lipid barrier 6, 5
• Pat skin dry with clean towels rather than rubbing to avoid further mechanical irritation 5
• Keep nails short to minimize trauma from scratching 6

Symptomatic relief for severe itching:

• Oral antihistamines (cetirizine 10mg, loratadine 10mg, or fexofenadina) once daily if itching significantly disrupts sleep or daily activities 5
• Note: Non-sedating antihistamines have limited benefit but may help severe pruritus 5

Critical Avoidance Measures

Eliminate mechanical triggers:

• Avoid basketball and similar activities for 7-10 days until inflammation resolves 3
• Identify and modify friction sources: Check for tight clothing, equipment straps, or repetitive arm movements that contact the affected area 9, 3
• Wear loose-fitting, smooth cotton clothing over affected areas 5

Prevent irritant exposure:

• Avoid hot water—use tepid water only for bathing, as heat worsens inflammation 5
• Avoid all alcohol-containing lotions, aftershaves, or topical products on affected skin, as these significantly worsen dryness 5, 9
• Do not apply topical acne medications or retinoids to the area, as these cause additional irritation 5
• Avoid scratching or rubbing the affected area, as manipulation increases infection risk and perpetuates inflammation 5, 8

Monitoring for Complications

Watch for secondary bacterial infection (requires antibiotic treatment):

• Increased crusting, weeping, or honey-colored discharge 6, 5
• Pustules or spreading erythema 6
• If present: Add oral flucloxacillin or cephalexin for Staphylococcus aureus coverage 5, 8

Watch for herpes simplex superinfection (rare but serious):

• Grouped vesicles or punched-out erosions 6, 5
• If present: Start oral acyclovir immediately 5, 8

Expected Timeline and Follow-Up

• Improvement should occur within 3-5 days of starting treatment 4
• Complete resolution expected within 7-10 days with proper treatment and trigger avoidance 8, 4
• If no improvement after 7 days or worsening at any time: Consider alternative diagnosis (allergic contact dermatitis, fungal infection) and refer to dermatology 5, 8

Return to Activity

• Resume basketball only after complete resolution of erythema and itching 3
• Implement preventive measures: Wear moisture-wicking clothing, apply barrier creams to friction-prone areas before activity, shower immediately after exercise 5, 3
• If recurrence occurs: Consider allergic contact dermatitis to sports equipment materials and pursue patch testing 6, 9

Common Pitfalls to Avoid

• Do not use high-potency corticosteroids (clobetasol, betamethasone) on the neck/chest initially—risk of skin atrophy and telangiectasia outweighs benefits for this mild-moderate presentation 6, 5
• Do not apply neomycin-containing products (Neosporin)—high sensitization rate (13-30%) can convert irritant dermatitis to allergic contact dermatitis 6, 9
• Do not confuse persistent mild itching after 7 days with treatment failure—hypersensitivity reactions can cause itching for weeks after inflammation resolves 6, 5
• Do not undertreate due to steroid fears—appropriate-potency topical corticosteroids for 7-10 days are safe and necessary for resolution 5, 8