Clinical Complications

Allergic Rhinitis (Hay Fever): Complications & Clinical Risks

Allergic rhinitis is an allergic response to allergens such as pollen, dust mites, or pet dander, causing sneezing, runny nose, nasal congestion, and itchy eyes. Seasonal (hay fever) and perennial types are the main categories.

Overview of Major Complications

Dermatological and allergic conditions generate complications through chronic skin barrier dysfunction, immune dysregulation, infection susceptibility, psychological impact, and in the case of severe allergic reactions, life-threatening anaphylaxis. While many skin conditions are primarily cosmetic in impact, the barrier breakdown in conditions like eczema creates a portal for bacterial and viral skin infections. Systemic inflammatory conditions like severe psoriasis carry significant cardiovascular and metabolic comorbidities. Anaphylaxis represents the most dangerous acute complication across the allergic disease spectrum.

Early Complications

  • ⚠Bacterial skin superinfection — Staphylococcus aureus impetigo and cellulitis in eczema and psoriasis
  • ⚠Eczema herpeticum — widespread HSV infection on eczematous skin; systemic dissemination risk
  • ⚠Anaphylaxis — in food allergy, drug allergy, or insect venom allergy; life-threatening within minutes
  • ⚠Acute urticaria and angioedema — airway oedema is the most dangerous manifestation
  • ⚠Contact dermatitis acute flare — vesicular dermatitis with weeping and crusting
  • ⚠Drug hypersensitivity reactions — Stevens-Johnson syndrome and toxic epidermal necrolysis are dermatological emergencies

Long-Term Complications

  • →Post-inflammatory hyperpigmentation — persistent discolouration after resolved active lesions
  • →Scarring — from severe acne, repeated cellulitis, or inadequately treated skin infections
  • →Psychosocial impact — depression, social withdrawal, and impaired quality of life in chronic skin disease
  • →Psoriatic arthritis — in 15–30% of psoriasis patients; joint erosion without early treatment
  • →Cardiovascular and metabolic comorbidities in psoriasis — increased BMI, metabolic syndrome
  • →Topical corticosteroid-induced atrophy — thinning and telangiectasia from inappropriate long-term use
  • →Sensitisation and allergy expansion — repeated allergen exposure broadens allergic repertoire
  • →Skin cancer — increased UV exposure risk in phototherapy recipients; immunosuppression risk in organ transplant

Emergency Complications

Immediate clinical action required

  • ✕Anaphylaxis — immediate IM adrenaline 0.5 mg; supine positioning; emergency services
  • ✕Stevens-Johnson syndrome/TEN — drug withdrawal, ICU management, burns unit care; high mortality
  • ✕Necrotising fasciitis — rare complication of cellulitis; surgical emergency with debridement
  • ✕Severe angioedema with airway compromise — IM adrenaline, IV antihistamines, early anaesthetic assessment
  • ✕Generalised pustular psoriasis — systemic illness with fever, neutrophilia; urgent dermatology admission

What Increases Complication Risk

  • ↑Skin barrier dysfunction — reduced filaggrin expression in atopic eczema drives sensitisation and infection
  • ↑Immunosuppressive therapy — increases herpes and bacterial skin infection risk
  • ↑Delay in allergen avoidance — repeated exposure worsens sensitisation
  • ↑Non-adherence to emollient regimens — recurrent eczema flares with superinfection
  • ↑Obesity — worsens psoriasis severity and reduces biologic efficacy
  • ↑Psychological stress — major trigger for psoriasis, eczema, and urticaria flares

What Reduces Complication Risk

  • ↓Regular emollient use — maintains skin barrier, reduces eczema flare frequency by 50%
  • ↓Allergen avoidance — cornerstone of food allergy and contact dermatitis management
  • ↓Adrenaline auto-injector prescription and training — prevents anaphylaxis mortality
  • ↓Appropriate biologic therapy (anti-IL-17, anti-IL-23) for moderate-severe psoriasis — clears skin and reduces joint disease
  • ↓Phototherapy under supervision — effective for psoriasis and eczema with skin cancer surveillance
  • ↓Early action on suspicious pigmented lesions — melanoma prognosis depends on Breslow thickness

When Urgent Reassessment is Needed

The following signs may indicate a new or worsening complication requiring prompt clinical evaluation:

  • ◆Urticaria with throat tightening, voice change, or syncope — anaphylaxis; IM adrenaline immediately
  • ◆Rapidly spreading cellulitis with blistering, dusky skin, or crepitus — necrotising fasciitis
  • ◆Eczema herpeticum — monomorphic punched-out erosions; systemic aciclovir urgently
  • ◆Drug rash with mucosal involvement, blistering, or fever — Stevens-Johnson syndrome; stop culprit drug
  • ◆Psoriasis with joint pain, morning stiffness, or nail changes — psoriatic arthritis review
  • ◆New pigmented lesion with asymmetry, irregular border, or rapid change — urgent dermatology assessment

Special Populations

Infants and children: eczema is most common in early childhood; food allergy testing important; moisturiser from birth reduces sensitisation risk
Elderly: thinner skin increases steroid atrophy risk; impaired healing; bullous pemphigoid is predominantly an elderly condition
Immunocompromised patients: atypical and severe presentations of skin infections; molluscum and warts can be extensive
Pregnant women: many systemic dermatological agents are teratogenic; emollients and low-potency topical steroids are safe; biologics require individual risk-benefit discussion

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Evidence & Guidelines

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Allergic Rhinitis (Hay Fever) Overview

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Medical References

Content on this page is informed by evidence-based clinical sources including: