top of page

N

Necrobiosis lipoidica 

Etiology: 
 

  • Histo: degenerated collagen, plasma cells, no mucin, “lasagna”

  • Ass. conditions: DM (not as strong as initially thought)

  • Description: reddish brown areas of the skin

  •  

  • Location: lower legs

  •  

  • Associated with: T1DM

Necrobiotic Xanthogranuloma

Etiology: 
 

  • Histo: X shaped red zones of necrosis within granuloma nodules; “peppered bacon”; cholesterol clefts

Necrolytic migratory erythema

Etiology: 
 

Cause: glucagonoma

 

Description: red, blistering rash that is itchy and painful 

 

Location: genitals, buttock, + groin

Necrotizing Fasciitis

Etiology: 

Causes: 

Type I: Klebsiella, E. coli, S. aureus, Pseudomonas

Type II: Strep. pyogenes

Type III: Clostridium

 

Description: necrosis of muscle and subcutaneous tissue presenting as red, warm, or swollen area of skin that spreads quickly; eventually can lead to dark purple coloration with crepitus; has pain out of proportion

 

Location: lower extremities, abdomen, perineum

 

At risk: diabetes, PVD, trauma, surgery, alcohol abuse, cirrhosis

Neonatal acne

Etiology: 

Neonatal purpura fulminans (NPF)

Etiology: 
 

Cause: homozygous protein C or S deficiency

 

Description: 

  1. Within 1st 72 hours after birth, purpuric lesions develop over perineal region, flexor surfaces and abdominal skin

  2. Enlarge and become hemorrhagic bullae with full thickness necrosis of skin and black eschar formation

Secondary infection leads to gangrene

Neuropathic Ulcer

Etiology: 
 

Cause: peripheral neuropathy (diabetic foot)

 

Description: hyperkeratotic edge with undermined borders and without pain

 

Location: bony prominences (metatarsal heads, heel)

Netherton Syndrome

Etiology: 
 

  • Define: rare, inherited disorder primarily affecting the skin, hair, and immune system; characterized by a triad of features: congenital ichthyosiform erythroderma (red, scaly skin from birth), hair shaft abnormalities (bamboo hair), and atopic diathesis 

  • Location: lateral eyebrows

  • Histo: trichorrhexis invaginata/bamboo hair (MC)

Nevus Comedonicus

Etiology: 
Tx: tretinoin

Nevus of Ito

Etiology: 
 

  • Appearance: blue, gray, or brown patch

  • Location: shoulder, upper arm, and side of the neck, typically in the distribution of the posterior supraclavicular and lateral cutaneous brachial nerves

Nevus of Ota

Etiology: 
 

  • Appearance: bluish-gray or brown-black pigmentation

  • Location: face, esp. around the eye

Nevus Sebaceous

Etiology: 
Location: scalp
Appearance: skin colored to yellow/orange plaque with cobblestone appearance

Nodular Fasciitis

Etiology: 
 

  • Define: no inflammation, benign tumor 

  • Histo: loose, whispy appearance of myofibroblasts, red cell extravasation; overtime become more myxoid and whispy 

Notalgia Paresthetica

Etiology: 
 

  • Define: sensory neuropathy that causes chronic, localized itching and sometimes pain, burning, or tingling 

  • Location: between shoulder blades (MC)

  • Tx: chiropractor work, capsaicin, gabapentin, CCS

Nummular Eczema

Etiology: 

bottom of page