What is the cause of a patient's red face and how should it be evaluated and treated, considering potential underlying conditions such as rosacea, allergic reactions, or cardiovascular disease?

Red Face: Diagnostic Approach and Management

Establish the Diagnosis

Begin by determining if persistent centrofacial erythema with periodic intensification is present—this alone is diagnostic of rosacea and is the most common cause of a red face in clinical practice. 1, 2

Key Diagnostic Features for Rosacea

• Persistent centrofacial erythema (cheeks, nose, chin, forehead) that intensifies with trigger factors (heat, exercise, alcohol, spicy foods) meets minimum diagnostic criteria for rosacea 1, 2
• Phymatous changes (thickened, irregular skin texture, particularly on the nose) are independently diagnostic of rosacea 1
• Telangiectasias on cheeks, nose, and ears are major features but not independently diagnostic 1, 2
• Stinging or burning sensation is a recognized minor feature 1, 2

Critical Ocular Evaluation

Immediately assess for ocular involvement in all patients with suspected rosacea, as ocular rosacea can cause sight-threatening complications including corneal perforation. 1, 2

• Ask specifically about: burning, stinging, dryness, foreign body sensation, recurrent styes 1, 2
• Examine for: blepharitis, meibomian gland dysfunction, conjunctival injection, corneal involvement 1, 2
• Children with ocular rosacea may present with corneal involvement before cutaneous manifestations appear, making early recognition critical 1, 2

Differential Diagnosis to Exclude

When the presentation is atypical or diagnosis uncertain, systematically exclude:

Life-Threatening Conditions (Red Swollen Face)

• Angioedema (mast cell-driven or bradykinin-mediated, hereditary or acquired) 3
• DRESS syndrome (drug reaction with eosinophilia and systemic symptoms) 3
• Necrotizing fasciitis, erysipelas, cellulitis 3
• Anaphylaxis 4

Systemic Diseases Causing Flushing

• Carcinoid syndrome, pheochromocytoma, mastocytosis require laboratory and radiologic workup 4
• Medullary thyroid carcinoma, pancreatic cell tumor, renal carcinoma are rare causes 4
• Cardiovascular disease may present with facial flushing 4

Other Dermatologic Conditions

• Contact dermatitis (allergic or photoallergic) 4, 3
• Photodermatoses (polymorphous light eruption, lupus erythematosus) 4, 5
• Dermatomyositis 5, 3
• Seborrheic dermatitis, acne, lupus 6

Treatment Algorithm for Confirmed Rosacea

For Inflammatory Papules/Pustules (Most Common Presentation)

First-line topical therapy:

• Ivermectin 1% cream is the preferred first-line agent 7
• Azelaic acid 15% gel/foam is an effective alternative 7
• Encapsulated benzoyl peroxide 5% shows rapid improvement by week 2 with sustained efficacy up to 52 weeks 1, 7

For moderate-to-severe inflammatory lesions:

• Add oral doxycycline 40 mg modified-release daily (anti-inflammatory dose with reduced GI side effects) 7
• Minocycline foam 1.5% for topical treatment of moderate-to-severe lesions 7

For Persistent Erythema

First-line vasoconstrictor therapy:

• Brimonidine tartrate 0.33% gel once daily (α2-adrenergic agonist) 1, 7
• Oxymetazoline HCl 1% cream once daily (α1-receptor agonist) as alternative 1, 7
• Warning: Both agents can cause paradoxical rebound erythema in 10-20% of patients 1

For Telangiectasias

• Pulsed-dye laser or intense pulsed light are primary treatments, as topical agents are ineffective 7

For Ocular Rosacea

• Mild symptoms: Lid hygiene and artificial tears 7
• Moderate-to-severe: Oral doxycycline 40 mg modified-release 7
• Ophthalmology referral for all but mildest cases 7

Essential Adjunctive Measures for All Patients

• Broad-spectrum sunscreen SPF 30+ daily (UV radiation activates inflammatory pathways) 2, 7
• Gentle cleansers and moisturizers 7
• Trigger avoidance: spicy foods, alcohol, extreme temperatures, hot beverages 7

Treatment Duration and Monitoring

• Allow 6-8 weeks for topical agents and 8-12 weeks for oral agents before declaring treatment failure 7
• Assess response at 4-6 weeks and evaluate each phenotypic feature independently 2
• Combination therapy is typically required for moderate-to-severe presentations 7

Maintenance Therapy

Without maintenance therapy, up to two-thirds of patients relapse when treatment is discontinued. 7

• Continue the minimum treatment necessary to maintain control 7
• Long-term management is essential given the chronic relapsing nature of rosacea 7

Critical Pitfalls to Avoid

• Do not overlook ocular manifestations—they can lead to permanent vision loss if untreated 1, 2
• Do not diagnose rosacea in children without considering ocular involvement first, as eye symptoms often precede skin findings 1
• Do not extrapolate acne treatment protocols to rosacea—the pathophysiology is fundamentally different 7
• Do not use traditional subtype classification—treat based on individual phenotypic features present 1, 7