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DERMATOLOGIC DISORDERS & NEUROMUSCULAR DISEASE

Flushing: Anticholinergic toxicity; Hypermagnesemia; Mercury; Erythermalgia
Petechiae or purpura: Vasculitis; Cryoglobulinemia; Alcoholism (Telangectasia); Amyloidosis
Pigment
- Hypo: Leprosy
- Hyper: POEMS; Neurofibromatosis; Adrenomyeloneuropathy
Thickening
- POEMS: Angiomas; Hirsutism
- Scleroderma: Sclerodactyly; Raynaud's
- Refsum: Ichthyosis
- CEDNIK: Ichthyosis; Palmoplantar keratoderma
- Muscular dystrophy, congenital, megaconial: Ichthyosis
Edema
- POEMS
- Amyloid
- Beriberi
- Pain Medications: Gabapentin; Lyrica
- Arsenic
Rash
- Infections
  - Leprosy: Focal hypopigmented; Erythema nodosum leprosum
  - Lyme: Erythema chronicum migrans
  - Syphilis: 1° chancre; 2° syphilis
  - Trichinosis: Periorbital edema
  - HIV: Seborrheic dermatitis (Pitysporum orbiculare); Kaposi's sarcoma
  - Herpes zoster
- Immune
  - Dermatomyositis
  - IMPP & Jo-1 myositis
  - Sarcoidosis: Hypohidrosis; Alopecia; Erythema nodosum; Scars & Keloids
- Toxic
  - Hexacarbon
  - Alcoholism: Malar rash
  - Arsenic: Scaly desquamation
- Hereditary
  - LHDA: Erythmatous or Psoriatic
- Other
  - Pellagra: Erythematous photosensitive rash; Hyperkeratotic
Finger nail change
- Mees lines: Arsenic; Thallium; Hexacarbon
- Splinter hemorrhage: Trichinosis; Dermatomyositis
- Dark pigmentation: Vitamin B₁₂ deficiency
- White: POEMS
Sweating: Autonomic disorders
Angiokeratomas: Fabry's
Ischemia: Calciphylaxis
Burns: Neuropathy
Ulcers
- Diabetes: Necrobiosis lipoidica diabeticorum; Poorly healing skin ulcers
- Sensory neuronopathy
Alopecia: Thallium; Sarcoidosis
Local infections: Diphtheria; Tetanus; Botulism
Venous insufficiency: Neuropathy
Osmiophilic vessels: Congenital spastic ataxia
Fibrosing Poikiloderma with Contractures, Myopathy & Pulmonary Fibrosis
Other
- Bethlem/Ullrich
- Blistering: Congenital Muscular Dystrophy with Familial Junctional Epidermolysis Bullosa
- Ehlers-Danlos, Variant
- Thinning: Xeroderma pigmentosum
Pemphigus: Associated with
- Thymoma & acquired myasthenia gravis & other immune disorders
- D-penicillamine induced syndrome
Nodular prurigo: Subclinical axonal sensory neuropathy ²
Erythrokeratodermia variabilis
- SCA34
- Hearing loss, Bilateral high-frequency + Sensory polyneuropathy

BURNS & NEUROPATHY

Burn severity
- Most (69%) > 20% surface area
- 28% full thickness
Patterns of neuropathy
- Mononeuritis multiplex (69%)
  - Onset: Recognized 10 to 124 days after burn
  - Especially Median, Ulnar & Peroneal
  - Localization: Regions near & remote from burn
- Mononeuropathy: Common in burned area; Arms > Legs
- Axonal polyneuropathy: Rare
- Electrical burns: Nerve lesions at entry area
Associated factors: Burn severity; Length of hospitalization
Systemic disorders: Sepsis; Renal failure; Low serum albumin
Rule out: Myosin-loss myopathy

VENOUS INSUFFICIENCY ¹

Neuropathy
- Clinical
  - Cramps (79%)
  - Pain: Dysesthesias; Paresthesias
  - Sensory loss: Vibration, Warm & Cold perception
- Electrophysiology
  - Prolonged distal motor latency in legs
  - Abnormal Aα, Aβ, Aδ & thermaoafferent C-fibers
  - Upper extremities: Normal
Skin
- Edema
- Venous dilation
- Pigmentation
- Ulceration
Laboratory
- Continuous wave Doppler: Reflux
- Duplex sonography: Reflux
- Plethysmography: Obstruction
- Phlebography: Reflux & Obstruction

Fibrosing Poikiloderma with Tendon Contractures, Myopathy & Pulmonary Fibrosis (POIKTMP) ³

● Family with sequence similarity 111, Member B (FAM111B)

; Chromosome 11q12.1; Dominant or de novo

Epidemiology: > 30 families
Genetics
- Mutations: Missense (Arg627Gly, Arg627Ser, Ser628Asn, Tyr621Asp); Nonsense; Splice
- Protease domain mutations: Systemic features more common
- Allelic disorder: Progressive Osseous Heteroplasia (Ossifications in muscle & skin)
FAM111B protein
- Location: Nuclei
- Catalytic: Contains trypsin-like cysteine/serine peptidase domain
- Complex with FAM111A
- Disease-associated FAM111B mutants: Amplified proteolytic activity
Clinical
- Onset
  - Age: Congenital or Early childhood
  - Poikiloderma
- Skin
  - Poikiloderma
    - Early onset
    - UV exposed areas
    - Face
    - Arms & Legs
  - Alopecia
  - Eczematous lesions
  - Erythema
  - Skin atrophy: Chronic
  - Hypohidrosis
  - Hair: Hypotrichosis, Alopecia, Sparse eyebows & lashes
  - Lymphedema (75%)
  - Pruritis
  - Treatments
    - Avoid of excessive sun & heat exposure
    - Sunscreens with UVA & UVB protection
    - Fever control
    - Topical steroids
  - Images: External links
    - Face
    - Limbs
- Weakness
  - Legs > Arms
  - Proximal & Distal
  - Amyotrophy
  - Course: Progressive
- Tendon reflexes: Reduced in Legs
- Pulmonary: Fibrosis
- Skeletal
  - Scoliosis: Thoracolumbar; Some patients
  - Contractures
    - Location: Distal legs; Arms (Elbow)
    - Progressive
  - Short stature
- Systemic
  - Esophagus & Pancreas: Fatty infiltration & Fibrosis
  - Hepatic ductulitis: Transaminases high
  - Pancreas: Exocrine insufficiency; Fatty stools, Diarrhea
  - Lungs: Fibrosis; Adult onset
  - Eye: Cataracts
- Course
  - Skin lesions: Resolution of some over time
  - Extracutaneous: Often progressive
- Diffferential diagnosis: Rothmund–Thomson syndrome (RTS)
Laboratory
- Serum CK: 300 to 600
- Liver enzymes: Midly high
- Blood: Eosinophilia, Thrombocytopenia, Bone marrow hypocellularity
- EMG: Myopathic or Normal
- Muscle MRI: Involvement
  - Anterior thigh compartment: Especially vastus lateralis
  - External link
- Muscle pathology
  - Replacement of muscle by fat & connective tissue
  - Fiber sizes: Fascicles with diffusely small or normal fibers
  - NCAM: Stains some small muscle fibers
  - ATPase: Normal
  - Focal nerve proliferation
  - External link
- Skin
  - Epidermis: Atrophy
  - Elastic fibers: Enlarged & fragmented in dermis
  - Collagen sclerosis
Differential diagnosis: Rothmund–Thomson syndrome

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References
1. Muscle Nerve 2000;23:883-887
2. Clin Exp Dermatol 2006 Oct 11
3. Am J Human Genet 2013; Online November, Gene Reviews

8/17/2021

DERMATOLOGIC DISORDERS & NEUROMUSCULAR DISEASE

BURNS & NEUROPATHY

VENOUS INSUFFICIENCY 1

Fibrosing Poikiloderma with Tendon Contractures, Myopathy & Pulmonary Fibrosis (POIKTMP) 3

VENOUS INSUFFICIENCY ¹

Fibrosing Poikiloderma with Tendon Contractures, Myopathy & Pulmonary Fibrosis (POIKTMP) ³