Skin Syndromes in Pediatrics

Staphylococcal Scalded Skin Syndrome (SSSS)

• Cause: Exotoxins (exfoliative toxins A and B) produced by Staphylococcus aureus.
• Affected group: Primarily neonates and young children.
• Pathophysiology: Toxins target desmoglein-1, causing epidermal cleavage in the stratum granulosum.
• Symptoms: Fever, irritability, skin tenderness, widespread erythema, superficial flaccid blisters, large sheets of epidermal peeling, positive Nikolsky sign (epidermis detaches with pressure), no mucosal involvement.
• Histology: Cleavage at the granular layer of the epidermis.
• Treatment: Antistaphylococcal antibiotics (oxacillin, clindamycin), supportive care (hydration, wound care).

Stevens-Johnson Syndrome (SJS)

• Cause: Severe immune-mediated hypersensitivity reaction, often triggered by drugs (e.g., sulfonamides, anticonvulsants) or infections (e.g., Mycoplasma pneumoniae).
• Affected group: All ages.
• Pathophysiology: Cytotoxic T cells induce keratinocyte apoptosis via Fas-Fas ligand interaction.
• Symptoms: Flu-like prodrome (fever, sore throat), erythematous macules progressing to targetoid lesions and epidermal detachment (less than 10% body surface area), prominent mucosal involvement (oral, ocular, genital), positive Nikolsky sign.
• Histology: Full-thickness epidermal necrosis.
• Treatment: Stop offending agent, supportive care in ICU/burn unit, consider immunomodulation (IVIG, corticosteroids) in select cases.

Toxic Epidermal Necrolysis (TEN)

• Cause: Similar to SJS (drug-induced hypersensitivity).
• Affected group: All ages, more severe in adults.
• Pathophysiology: Extensive keratinocyte apoptosis due to cytotoxic T-cell activity.
• Symptoms: Similar to SJS but involves greater than 30% body surface area, severe skin and mucosal involvement, widespread sloughing of epidermis, positive Nikolsky sign, systemic complications (dehydration, infection, multi-organ failure).
• Histology: Full-thickness epidermal necrosis with subepidermal detachment.
• Treatment: Stop causative drug, aggressive supportive care (fluid replacement, wound care, temp control), IVIG or immunosuppressive therapy (controversial).

Erythema Multiforme (EM)

• Cause: Immune-mediated hypersensitivity reaction, most commonly triggered by infections (especially Herpes simplex virus (HSV)), less frequently by drugs (e.g., sulfonamides, NSAIDs, anticonvulsants).
• Pathophysiology: Type IV hypersensitivity reaction, immune response leading to immune complex deposition in small dermal blood vessels and inflammation.
• Symptoms: Target lesions (central dusky/blistered area, pale edematous ring, erythematous halo), symmetrical involvement (palms, soles, extensor surfaces, mucocutaneous junctions), lesions can coalesce but usually discrete, mild mucosal involvement (oral ulcers, conjunctivitis, genital erosions) in EM Major, mild systemic symptoms (fever, malaise).
• Classification: EM Minor (skin only, minimal mucosal involvement) and EM Major (mucosal involvement).
• Differences from SJS/TEN: Less severe, usually self-limiting, target lesions, negative Nikolsky sign and less severe mucosal involvement, infections are frequent triggers, drugs less frequent. EM lesions usually remain discrete.
• Treatment: Identify and treat underlying cause (e.g., antivirals for HSV), supportive care (hydration, analgesics, topical steroids). EM Major may require systemic corticosteroids or hospitalization, recurrent EM may need prophylactic antivirals if HSV is a trigger.