Introduction
Lightning strikes are among nature’s most powerful electrical phenomena, capable of generating currents exceeding 30,000 amperes and temperatures hotter than the sun’s surface. While most victims of lightning survive, they often present with unusual cutaneous and systemic manifestations. Among these, the filigree burn, also known as the Lichtenberg figure, remains one of the most striking and diagnostically distinctive patterns in clinical dermatology.
This article explores the pathophysiology of filigree burns, the diverse dermatological and systemic consequences of lightning, and other rare but related skin conditions caused by environmental or electrical exposure.
1. Filigree Burns (Lichtenberg Figures)
Definition
Filigree burns, also known as arborescent or Lichtenberg figures, are transient, fern-like erythematous skin markings that occur following a lightning strike or high-voltage electrical discharge.
Appearance
They typically appear as reddish, branching, superficial patterns resembling the outline of tree branches or ferns, often seen on the shoulders, chest, back, or limbs. They are not true burns, but rather dermal capillary ruptures due to the passage of intense electrical energy and resultant electron shower effect.
Pathophysiology
When lightning current travels over or through the body, it can cause:
- Electron showering in the skin.
- Capillary rupture without epidermal destruction.
- Transient erythema due to vasomotor response.
These marks usually fade within 24–48 hours, leaving no scarring — a distinguishing feature from thermal or electrical burns.
Clinical Significance
- Pathognomonic of lightning injury.
- Help in forensic identification in cases of unexplained death outdoors.
- May coexist with deep electrical burns if the lightning current penetrates deeply.
2. Other Cutaneous Manifestations of Lightning Injury
Lightning can affect the skin in multiple ways depending on the type of contact, the pathway of current, and the surrounding environment.
a. Linear Burns
- Appear as narrow, superficial burns in a line pattern.
- Caused by rapid vaporization of sweat or rainwater on the skin surface.
- Usually painless and heal well.
b. Punctate Burns
- Small circular burns at points where metallic objects (like jewelry, coins, or belt buckles) were present.
- Result from localized heating of metal conductors.
c. Thermal Burns
- Secondary to ignition of clothing or contact with hot metal.
- Often deep and may require surgical management.
d. Flashover Burns
- When the lightning current travels over rather than through the body.
- Usually cause superficial injury but may accompany internal organ damage due to electrical fields.
3. Systemic and Neurological Consequences
Though the skin often shows the most visible evidence, lightning primarily affects deeper organs:
- Cardiac: Asystole or ventricular fibrillation due to electrical depolarization.
- Neurological: Seizures, transient paralysis (keraunoparalysis), amnesia, or autonomic dysfunction.
- Ocular: Cataract formation, corneal burns.
- Auditory: Tympanic membrane rupture from the thunderclap pressure wave.
4. Other Rare Skin Conditions Related to Environmental or Electrical Exposure
a. Keraunographic Tattoos
Permanent skin pigmentation due to embedded metallic or carbon particles from an explosive lightning strike.
Unlike Lichtenberg figures, these do not fade and may require laser or surgical treatment.
b. Joule Burns
Seen in industrial electrical injuries.
Result from resistive heating at the entry and exit points of electric current, producing deep coagulative necrosis — often necessitating grafting or amputation.
c. Cryogenic Burns
Occur due to contact with supercooled liquids or gases (liquid nitrogen, refrigerants).
Mimic thermal burns but are due to cold-induced tissue damage.
d. Phytophotodermatitis
A rare phototoxic reaction caused by plant-derived furocoumarins (e.g., lime, celery, fig) followed by UV exposure.
Produces bizarre streaky or drip-patterned hyperpigmented lesions — often mistaken for burns or abuse marks.
e. Radiation-Induced Skin Injuries
Seen in patients exposed to ionizing radiation, either accidentally or therapeutically.
Manifestations range from erythema and desquamation to chronic ulceration and radiation-induced dermatitis.
5. Diagnostic Approach
- History: Exposure to storm, electrical source, or chemical/environmental agents.
- Examination: Pattern recognition — arborescent (lightning), linear/punctate (thermal), irregular (chemical).
- Investigations:
- ECG and cardiac monitoring.
- Serum electrolytes, CK, renal function (for rhabdomyolysis).
- Ophthalmic and neurological evaluation.
6. Management
- Immediate: Cardiopulmonary resuscitation if cardiac arrest.
- Local care: Cleanse wounds, topical antibiotics for superficial burns.
- Systemic: IV fluids, analgesia, tetanus prophylaxis.
- Rehabilitation: Psychological support, physiotherapy for neuropathy or paralysis.
7. Prognosis
Most lightning-related cutaneous lesions heal without scarring.
However, long-term neurological or psychological sequelae are common — including chronic pain, memory deficits, and post-traumatic stress disorder (PTSD).
Conclusion
Filigree burns, or Lichtenberg figures, remain one of nature’s most fascinating dermatological signatures — transient, beautiful, and dangerous reminders of the immense energy that lightning delivers. Recognizing these and other rare cutaneous consequences is crucial not only for prompt clinical management but also for forensic and educational purposes.
Equally, understanding similar environmental skin injuries broadens a clinician’s diagnostic insight into unusual dermatological presentations.