Dermatitis Due to Sun Exposure

Sun-induced dermatitis, also known as photodermatitis, is an inflammatory skin reaction triggered by exposure to ultraviolet (UV) radiation from the sun. This condition encompasses various photosensitivity disorders that can range from mild redness to severe blistering reactions. While anyone can develop sun-induced dermatitis, certain individuals are more susceptible due to genetic factors, medications, or underlying medical conditions.

Quick Facts

  • Prevalence: Affects up to 20% of the population to varying degrees
  • Common Types: Phototoxic, photoallergic, and polymorphous light eruption
  • Onset: Can occur within minutes to days after sun exposure
  • Prevention: Highly preventable with proper sun protection

Overview

Dermatitis due to sun exposure represents a spectrum of skin conditions triggered by ultraviolet radiation. Unlike a typical sunburn, which occurs from excessive UV exposure in anyone, photodermatitis involves an abnormal reaction to UV light that can occur even with minimal sun exposure. This heightened sensitivity can be inherent (primary photosensitivity) or induced by external factors such as medications or chemicals (secondary photosensitivity).

The skin's reaction to UV radiation in photodermatitis involves complex immunological and biochemical processes. When UV light interacts with certain molecules in or on the skin, it can create reactive compounds that damage skin cells and trigger an inflammatory response. This reaction can manifest in various ways, from immediate burning sensations to delayed eruptions appearing days after exposure.

Understanding photodermatitis is crucial in our sun-exposed world. While moderate sun exposure provides beneficial vitamin D synthesis, individuals with photosensitivity must carefully balance their sun exposure to avoid painful and potentially scarring reactions. The condition significantly impacts quality of life, affecting outdoor activities, occupational choices, and even simple daily tasks like driving or walking outside.

Symptoms

Sun-induced dermatitis presents with various symptoms that typically appear on sun-exposed areas:

Primary Skin Symptoms

Secondary Symptoms

Associated Symptoms

  • Lack of growth - In children with severe photosensitivity
  • Fever and chills (in severe reactions)
  • Headache
  • Nausea
  • Fatigue

Distribution Pattern

  • Face, neck, and V-area of chest
  • Dorsal hands and forearms
  • Exposed areas of legs
  • Sparing of covered areas
  • Sharp demarcation at clothing lines

Seek Immediate Medical Attention For:

  • Severe blistering covering large body areas
  • Signs of infection (pus, red streaks, fever)
  • Severe pain unresponsive to treatment
  • Eye involvement or vision changes
  • Signs of systemic reaction (difficulty breathing, swelling)
  • Confusion or altered mental state

Types

Sun-induced dermatitis encompasses several distinct conditions:

Phototoxic Dermatitis

  • Mechanism: Direct cellular damage from UV-activated chemicals
  • Onset: Within minutes to hours of exposure
  • Appearance: Exaggerated sunburn with sharp demarcation
  • Common triggers:
    • Medications (tetracyclines, NSAIDs, diuretics)
    • Plant compounds (psoralens in limes, celery)
    • Fragrances and cosmetics

Photoallergic Dermatitis

  • Mechanism: Immune-mediated reaction to UV-altered substances
  • Onset: 24-72 hours after exposure
  • Appearance: Eczematous, may spread beyond exposed areas
  • Common triggers:
    • Sunscreens (especially benzophenones)
    • Aftershave lotions
    • Topical NSAIDs
    • Antibacterial agents

Polymorphous Light Eruption (PMLE)

  • Most common idiopathic photodermatosis
  • Onset: Hours to days after first intense exposure
  • Appearance: Various forms - papules, plaques, vesicles
  • Characteristics:
    • Often improves with continued exposure (hardening)
    • Recurs each spring/summer
    • More common in women
    • Hereditary tendency

Solar Urticaria

  • Rare immediate reaction
  • Onset: Within minutes of exposure
  • Appearance: Hives on exposed areas
  • Duration: Usually resolves within hours
  • Can cause anaphylaxis in severe cases

Chronic Actinic Dermatitis

  • Severe, persistent photosensitivity
  • Affects older men predominantly
  • Year-round symptoms
  • May react to visible light as well as UV
  • Thickened, eczematous skin changes

Photoaggravated Dermatoses

Pre-existing conditions worsened by sun exposure:

  • Lupus erythematosus
  • Dermatomyositis
  • Rosacea
  • Atopic dermatitis
  • Seborrheic dermatitis

Causes

Sun-induced dermatitis results from abnormal skin reactions to UV radiation, often triggered by various factors:

Medications (Drug-Induced Photosensitivity)

  • Antibiotics:
    • Tetracyclines (doxycycline, minocycline)
    • Fluoroquinolones (ciprofloxacin, levofloxacin)
    • Sulfonamides
  • Cardiovascular drugs:
    • Thiazide diuretics
    • Amiodarone
    • ACE inhibitors
    • Calcium channel blockers
  • NSAIDs:
    • Naproxen
    • Piroxicam
    • Ketoprofen
  • Other medications:
    • Retinoids
    • Phenothiazines
    • Oral contraceptives
    • Chemotherapy agents

Topical Agents

  • Fragrances and cosmetics:
    • Musk ambrette
    • Bergamot oil
    • Lavender oil
    • Sandalwood oil
  • Sunscreen ingredients:
    • Benzophenones
    • PABA derivatives
    • Cinnamates
  • Industrial chemicals:
    • Coal tar derivatives
    • Dyes
    • Petroleum products

Plant-Related (Phytophotodermatitis)

  • Psoralen-containing plants:
    • Limes and other citrus fruits
    • Celery
    • Parsnips
    • Figs
    • Wild parsley
  • Garden plants:
    • Giant hogweed
    • Rue
    • St. John's wort

Medical Conditions

  • Genetic disorders:
    • Xeroderma pigmentosum
    • Porphyrias
    • Bloom syndrome
    • Cockayne syndrome
  • Autoimmune diseases:
    • Lupus erythematosus
    • Sjögren's syndrome
    • Dermatomyositis
  • Metabolic disorders:
    • Pellagra (niacin deficiency)
    • Hartnup disease

Risk Factors

Several factors increase the risk of developing sun-induced dermatitis:

Skin Characteristics

  • Fair skin (Fitzpatrick types I-II)
  • Light-colored eyes and hair
  • Freckling tendency
  • History of severe sunburns
  • Presence of many moles

Geographic and Environmental

  • High altitude locations
  • Proximity to equator
  • Reflective surfaces (snow, water, sand)
  • Time of day (10 AM - 4 PM)
  • Season (spring/summer)
  • Ozone depletion areas

Occupational Risks

  • Outdoor workers (construction, agriculture)
  • Lifeguards and beach workers
  • Ski instructors
  • Military personnel
  • Pilots and flight attendants

Medical History

  • Previous photosensitivity reactions
  • Family history of photodermatoses
  • Autoimmune diseases
  • Organ transplant recipients
  • HIV/AIDS patients
  • Cancer treatment history

Lifestyle Factors

  • Tanning bed use
  • Outdoor recreational activities
  • Inadequate sun protection habits
  • Use of photosensitizing products
  • Alcohol consumption (increases photosensitivity)

Diagnosis

Accurate diagnosis of sun-induced dermatitis requires comprehensive evaluation:

Medical History

  • Detailed sun exposure history
  • Timing of symptom onset relative to exposure
  • Pattern and distribution of eruption
  • Medication history (prescription and OTC)
  • Topical product use
  • Occupational and recreational exposures
  • Family history of photosensitivity
  • Previous episodes and triggers

Physical Examination

  • Distribution analysis:
    • Sun-exposed vs. covered areas
    • Sharp demarcation lines
    • Sparing of shaded areas (under chin, eyelids)
  • Morphology assessment:
    • Type of lesions (macules, papules, vesicles)
    • Presence of scaling or lichenification
    • Signs of secondary infection

Diagnostic Tests

  • Phototesting:
    • Minimal erythema dose (MED) testing
    • UVA and UVB testing separately
    • Visible light testing if indicated
  • Photopatch testing:
    • Identifies photoallergic reactions
    • Duplicate patch test with UV exposure
    • Standard photoallergen series
  • Laboratory tests:
    • ANA and anti-Ro/La antibodies (lupus)
    • Porphyrin studies (urine, stool, blood)
    • Complete blood count
    • Liver and kidney function
  • Skin biopsy:
    • If diagnosis unclear
    • Shows specific patterns for different conditions
    • Direct immunofluorescence if indicated

Provocative Testing

  • Controlled UV exposure
  • Reproduction of symptoms
  • Determination of action spectrum
  • Should be done in specialized centers

Treatment

Treatment focuses on managing acute symptoms and preventing future reactions:

Acute Management

  • Immediate measures:
    • Move to shade/indoors immediately
    • Cool compresses or baths
    • Avoid further sun exposure
    • Remove photosensitizing agents if identified
  • Topical treatments:
    • Corticosteroids (moderate to high potency)
    • Calcineurin inhibitors for face/intertriginous areas
    • Emollients and moisturizers
    • Calamine lotion for itch relief
  • Systemic treatments:
    • Oral antihistamines for pruritus
    • Oral corticosteroids for severe cases
    • NSAIDs for pain and inflammation
    • Antibiotics if secondary infection

Chronic Management

  • Photoprotection (essential):
    • Broad-spectrum sunscreen (SPF 30+)
    • Physical barriers (clothing, hats)
    • UV-protective window films
    • Behavioral modification
  • Systemic therapies:
    • Hydroxychloroquine for PMLE
    • Beta-carotene supplementation
    • Nicotinamide (vitamin B3)
    • Omega-3 fatty acids
  • Phototherapy (paradoxical treatment):
    • Narrowband UVB for desensitization
    • PUVA for severe cases
    • Gradual hardening protocols
    • Must be carefully monitored

Specific Treatments by Type

  • Phototoxic reactions:
    • Discontinue causative agent
    • Symptomatic relief
    • Usually resolves in days
  • Photoallergic reactions:
    • Identify and avoid allergen
    • May require systemic steroids
    • Patch testing after resolution
  • PMLE:
    • Prophylactic phototherapy
    • Antimalarials
    • Topical steroids for flares
  • Solar urticaria:
    • H1 antihistamines
    • Phototherapy desensitization
    • Omalizumab for severe cases

Alternative and Supportive Therapies

  • Aloe vera gel for soothing
  • Green tea compresses (antioxidant)
  • Vitamin C and E supplementation
  • Stress management techniques
  • Dietary modifications (antioxidant-rich foods)

Prevention

Prevention is the cornerstone of managing sun-induced dermatitis:

Sun Protection Strategies

  • Sunscreen use:
    • Broad-spectrum SPF 30 or higher
    • Apply 30 minutes before exposure
    • Reapply every 2 hours
    • Water-resistant formulations for swimming
    • Use 1 ounce (shot glass) for full body
  • Protective clothing:
    • UPF-rated fabrics
    • Long sleeves and pants
    • Wide-brimmed hats (3-inch brim)
    • UV-blocking sunglasses
    • Gloves for hand protection
  • Behavioral modifications:
    • Avoid peak UV hours (10 AM - 4 PM)
    • Seek shade whenever possible
    • Plan outdoor activities wisely
    • Check UV index daily
    • Use UV detection apps

Medication Management

  • Review all medications with healthcare provider
  • Identify photosensitizing drugs
  • Consider alternative medications when possible
  • Time medication doses appropriately
  • Read all medication warnings

Environmental Modifications

  • Install UV-blocking window films
  • Use UV-protective car window tinting
  • Create shaded outdoor spaces
  • Choose indoor exercise alternatives
  • Modify work environment if needed

Lifestyle Adaptations

  • Gradual sun exposure for hardening
  • Maintain healthy vitamin D levels
  • Stay hydrated
  • Avoid tanning beds completely
  • Educate family members about condition

Travel Precautions

  • Research UV levels at destination
  • Pack adequate sun protection
  • Consider travel insurance
  • Identify medical facilities
  • Adjust activities based on sun exposure

Complications

While often manageable, sun-induced dermatitis can lead to various complications:

Acute Complications

  • Secondary infection:
    • Bacterial (impetigo, cellulitis)
    • Viral (herpes simplex reactivation)
    • Fungal in moist areas
  • Severe systemic reactions:
    • Dehydration
    • Electrolyte imbalances
    • Heat exhaustion
    • Anaphylaxis (rare)
  • Eye complications:
    • Photokeratitis
    • Conjunctivitis
    • Temporary vision changes

Chronic Complications

  • Skin changes:
    • Hyperpigmentation
    • Hypopigmentation
    • Scarring
    • Premature aging
    • Actinic keratoses
  • Psychological impact:
    • Anxiety about sun exposure
    • Social isolation
    • Depression
    • Reduced quality of life
    • Activity limitations
  • Economic burden:
    • Medical costs
    • Lost work productivity
    • Lifestyle modifications expenses
    • Special clothing/products

Long-term Risks

  • Skin cancer risk:
    • Increased with chronic inflammation
    • Especially with immunosuppression
    • Regular screening essential
  • Chronic actinic damage:
    • Solar elastosis
    • Telangiectasias
    • Actinic purpura

Treatment Complications

  • Topical steroid side effects
  • Systemic medication toxicity
  • Phototherapy burns
  • Contact dermatitis from sunscreens

When to See a Doctor

Knowing when to seek medical attention is crucial for proper management:

Seek Emergency Care For:

  • Severe blistering over large body area
  • Signs of infection (fever, pus, red streaks)
  • Difficulty breathing or swallowing
  • Severe swelling of face or lips
  • Confusion or altered mental state
  • Signs of heat stroke
  • Severe eye pain or vision loss

Schedule an Appointment For:

  • First episode of unusual sun reaction
  • Recurring sun sensitivity
  • Reaction while using new medication
  • Rash not improving after 1 week
  • Spreading beyond sun-exposed areas
  • Associated systemic symptoms
  • Need for preventive strategies

Dermatology Referral Indicated For:

  • Unclear diagnosis
  • Need for phototesting
  • Severe or resistant cases
  • Consideration of phototherapy
  • Multiple photosensitizing medications
  • Occupational photosensitivity

Regular Follow-up Needed If:

  • Chronic photodermatosis diagnosed
  • On long-term treatment
  • History of severe reactions
  • Multiple trigger factors
  • Skin cancer surveillance needed

Prevention Consultation

  • Before starting photosensitizing medication
  • Planning outdoor occupation
  • Moving to sunny climate
  • Family history of photodermatoses
  • Previous skin cancer