Dermatological Conditions

Skin-Eye Connection - Kindred Tissues

• Shared Embryology: Skin & eye structures derive from common germ layers.
  • Surface Ectoderm: Forms epidermis, corneal & conjunctival epithelium, lens.
  • Neural Crest Cells: Contribute to dermis, uveal melanocytes, corneal stroma & endothelium.
• Clinical Link: Dermatological disorders frequently exhibit ocular signs due to this shared origin.

  ⭐ Neurocutaneous syndromes (phakomatoses) like Neurofibromatosis, Tuberous Sclerosis, Sturge-Weber syndrome classically show skin-eye co-manifestations.

SJS/TEN & Pemphigoid - Bubble Trouble Eyes

• Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN)

  • Acute, severe mucocutaneous reactions; often drug-induced (e.g., sulfonamides, anticonvulsants).
  • Ocular: Acute bilateral conjunctivitis (papillary/membranous/pseudomembranous), lid edema, erosions, keratitis, corneal ulceration/perforation, symblepharon, ankyloblepharon, severe dry eye, trichiasis, entropion.
  • Systemic: Fever, malaise, widespread blistering, mucosal involvement (oral, genital).

• Ocular Cicatricial Pemphigoid (OCP)

  • Chronic, autoimmune blistering disease affecting mucous membranes (Type II hypersensitivity).
  • Ocular: Progressive conjunctival fibrosis, subepithelial bullae → scarring, symblepharon (key feature), ankyloblepharon, forniceal shortening, trichiasis, entropion, severe dry eye, corneal opacification, blindness.
  • Systemic: Oral lesions (desquamative gingivitis), skin, other mucosae.

⭐ Symblepharon (adhesion between palpebral and bulbar conjunctiva) is a hallmark of both severe SJS/TEN sequelae and OCP, leading to restricted ocular motility and dry eye. Early intervention is critical to prevent long-term vision loss.

📌 SJS/TEN: Sudden Jolt Skin / Terrible Epidermal Necrosis. 📌 OCP: Old Cicatrices Persist (chronic scarring).

Atopy, Psoriasis, Rosacea - Inflamed Views

• Atopic Dermatitis (AD): Chronic, itchy skin inflammation.
  • Ocular: Atopic keratoconjunctivitis (AKC), eyelid dermatitis/eczema, Dennie-Morgan folds (infraorbital), Hertoghe's sign (lateral eyebrow thinning).
  • Complications: Keratoconus, anterior subcapsular cataracts, ↑ risk of retinal detachment.

  ⭐ AKC is a chronic, bilateral inflammation often associated with vernal-like shield ulcers and limbal Horner-Trantas dots.

• Psoriasis: Chronic inflammatory skin disease.
  • Ocular: Chronic non-granulomatous anterior uveitis (most common, often HLA-B27+), conjunctivitis, blepharitis, dry eye, punctate keratitis, madarosis.
• Rosacea: Chronic facial dermatosis.
  • Ocular: Ocular rosacea (affects up to 50-75% of patients), posterior blepharitis, meibomian gland dysfunction (MGD), recurrent chalazia/hordeola, marginal keratitis, stromal keratitis, conjunctival hyperemia.

Genodermatoses & Behçet's - Systemic Signs

• Xeroderma Pigmentosum (XP)
  • DNA repair defect; ↑ UV sensitivity
  • Systemic: Skin cancers (BCC, SCC, melanoma)
• Ichthyosis
  • Keratinization disorder; dry, scaly skin
  • Systemic: Sjögren-Larsson syndrome (spasticity, intellectual disability)
• Atopic Dermatitis (Eczema)
  • Chronic inflammatory skin disease
  • Systemic: Allergic rhinitis, asthma (atopic triad)
• Pseudoxanthoma Elasticum (PXE)
  • Elastic fiber degeneration
  • Systemic: Skin (yellow papules - neck, axillae); Cardiovascular (calcification, hemorrhage); GI bleeds
• Behçet's Disease
  • Multisystem vasculitis
  • Systemic: Recurrent oral & genital ulcers; Skin lesions (erythema nodosum, papulopustular lesions); Arthritis; GI/CNS involvement
  • Pathergy test positive

⭐ Behçet's disease shows a strong association with HLA-B51.

High‑Yield Points - ⚡ Biggest Takeaways

• SJS/TEN: Severe drug reactions; cause cicatricial conjunctivitis, keratinization, symblepharon, severe dry eye.
• Atopic Dermatitis: Linked to atopic keratoconjunctivitis (AKC), anterior subcapsular cataracts, keratoconus.
• Ocular Rosacea: Features chronic blepharitis, MGD, recurrent chalazia, peripheral keratitis.
• Psoriasis: Associated with uveitis (anterior), conjunctivitis, blepharitis, dry eye.
• Ocular Cicatricial Pemphigoid: Autoimmune; causes progressive conjunctival scarring, symblepharon, corneal blindness.
• Xeroderma Pigmentosum: DNA repair defect; high risk of UV-induced ocular surface neoplasms and eyelid cancers.