Dermatology - Scaling Disorders

From Iusmicm

Contents 1 Scaling Disorders 1.1 Psoriasis 1.2 Pityriasis rosea 1.3 Secondary syphillis 1.4 Lichen planus 1.5 Chronic dermatitis: Atopic dermatitis 1.6 Chronic dermatitis: Seborrheic dermatitis 1.7 Chronic dermatitis: Stasis dermatitis 1.8 Ichthyosis 1.9 Superficial fungal infections

[edit] Scaling Disorders

• Scaling disorders are called papulosquamous: something you can feel + scaling
• Scale comes from the French word escale and the English skale which mean a substance that separates like a husk.
• Rash comes from the French word rache meaning "eruption" and the Latin radere meaning "sracth" indicating the sudden appearance and severity of a rash.
• Scaling rashes usually generate excess keratinocytes.

[edit] Psoriasis

• The prototypical scaling rash
• Biblical leprosy may actually be referencing psoriasis

• Cutaneous characteristics:
  • Well-defined erythematous papules and plaques with silvery scaling
  • Distribution: symmetrical, at extensor surfaces (elbows and knees), buttocks
  • Erythroderma (abnormal redness); "red man syndrome"
    • Can be so bad they have a hard time maintaining temperature and water balance
    • Redness almost always followed by peeling
  • 7-fold faster epidermal production (every 3-4 days), thus a thickening
  • Common sites: extensor surfaces (elbows, knees), sacrum, trauma sites (Koebner phenomenon), scalp, heel
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• Histological characteristics:
  • Inflammation
  • Parakeratosis (retention of nuclei in keratinocytes)
  • Acanthosis (thickening of the epidermis)=
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• Non-cutaneous characteristics:
  • Nail involvement: pits, onycholysis (nail separation)
    • Lots of nail pits indicates likely joint issues, too.
  • Arthritis in 5% of pts
  • Increased risk for metabolic disease and cardiac-related infections
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• Clinical characteristics:
  • Scales may be minimal or masked by hydration
  • Onset can be at any age.
  • Has a genetic predisposition: family history positive in 1/3 of cases
  • Can be precipitated by: infection, trauma, or drugs.
  • Can actually IMPROVE with sun exposure.
    • Koebner phenomenon describes how lesions tend to occur at sites of trauma.
    • Often arises after streptococcal pharyngitis; think superantigens
  • Note that potent topical steroid treatment leads to permanent stria!
    • Be careful where you apply topical steroids: don't use it on genitals or faces
  • PUBA sensitizes cells to ultraviolet and kills the excessively dividing cells

• Psoriasis subtypes:
  • Acute onset Guttate psoriasis
    • Guttate = teardrop in shape
    • "Guttate psoriasis is characterized by teardrop-size pink papules that often develop in response to a streptococcal or other upper respiratory tract infection. The lesions are much smaller than those of psoriasis vulgaris; however, this usually shortlived condition can evolve into chronic psoriatic disease." per ConsultLive
    • Associated with strep infection
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  • Perineal psoriasis
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• Other images of psoriasis:
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  • http://images.emedicinehealth.com/images/4453/4453-13248-31078-31450.bmp

[edit] Pityriasis rosea

• Cutaneous characteristics of pityriasis rosea:
  • Comes in several forms of color, shape, and lesion type:
    • Shape: round OR oval
    • Color: pink OR brown
    • Lesion type: macules / patches (non-palpable, discolored) OR papules / plaques (raised)
  • Herald patch: heralds the coming of the infection
  • Much thinner than psoriasis
  • No nail involvement with PR
  • Papular version (Herald patches): more inflammatory version; red, irregular, papules with a scale within the erythmatous border
  • Classic presentation: red-yellow, oval / round, (thin) plaques with trailing scale; oriented along cleavage lines
  • Symmetry: distributed over both sides of the trunk
  • Distribution: primarily truncal; follows skin lines; "oriented along cleavage lines"
  • Mild puritis
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• Histological characteristics of pityriasis rosea:
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• Clinical characteristics of pityriasis rosea:
  • Acute, self-limiting
  • Unknown cause, though probably herpes
    • Weird pattern of spread: entire classroom yet not within a family
  • Consider secondary syphillis in the differential of pityriasis rosea

[edit] Secondary syphillis

• Cutaneous characteristics:
  • Chancres!
    • Will go away on its own, often
  • Copper pennies with scaling
    • More brown-ish than red
    • Teeming with spirochetes
    • On palms or soles
  • Distribution: mouth, genitalia / anus (condyloma lata), palms of hands, planar surface of feet, back,
  • Condyloma lata look like warts but won't respond to wart tx.
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  • http://infections.consultantlive.com/image/image_gallery?img_id=1400637&t=1239393788816
  • http://infections.consultantlive.com/image/image_gallery?img_id=1400629&t=1239628194012
  • http://infections.consultantlive.com/image/image_gallery?img_id=1400641&t=1239393788843
  • http://infections.consultantlive.com/image/image_gallery?img_id=1400645&t=1239393788865
  • http://infections.consultantlive.com/image/image_gallery?img_id=1400653&t=1239393788926
  • http://infections.consultantlive.com/image/image_gallery?img_id=1400657&t=1239628194124
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• Non-cutaneous characteristics of secondary syphillis (a systemic disease):
  • Fever
  • Mucous membranes
  • Headache
  • Enlarged lymph nodes

• Clinical characteristics of secondary syphillis:
  • A systemic disease!
  • If you suspect syphillis put on gloves!
  • Blood tests are nearly 100% sensitive / specific so if you get a positive, they have it.
  • 1/3 of untreated cases will resolve on their own without incident

• Other images of secondary syphillis:
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[edit] Lichen planus

• Cutaneous characteristics of lichen planus:
  • Pruritus: really, really, really itchy!
  • Four P's: purple, polygonal, pruritic, papules / plaques.
  • Look like lichen ("A simple slow-growing plant that typically forms a low crustlike, leaflike, or branching growth on rocks, walls, and trees" per Google)
  • An inflammatory cutaneous and mucosal membrane disease
  • 'Flat topped papules / plaques that are violaceous (violet in color, "more purple than expected") and scaling
  • Key word is Whickham striae which are the white lacy patterns.
    • These can look like psoriasis but they are purple not red.
  • Distribution: trunk and extremities, especially the wrists and distal leg, oral mucosa
  • Note that if the oral lacy formations don't scrape off, it isn't candida and it is likely lichen planus
  • Can present as similar to graft-versus-host disease'
  • Demonstrates "Koebner phenomenon" (occurring near sites of trauma / scratching)
    • Results in linear distribution when due to scratching
    • Recall that psoriasis, too, demonstrates Koebner phenomenon
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• Clinical characteristics of lichen planus:
  • Unknown cause (like pityriasis rosea)
  • Not contagious
  • Abrupt onset
  • Skin and mucosal membrane involvement
  • Hard to treat
  • Can include the nail

[edit] Chronic dermatitis: Atopic dermatitis

• Cutaneous characteristics of atopic dermatitis:
  • Erythema with lichenification, excoriations, crusting, and pruritis
    • Lichenification: looks like a washboard and requires 200k sratches
  • Pruritis
  • Distribution: flexor surfaces (popliteal fossa, cubital fossa, posterior cervical region), cheeks
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• Non-cutaneous characteristics of atopic dermatitis:
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• Clinical characteristics of atopic dermatitis:
  • Associated with asthma / hayfever
  • Family history is important
  • Elevated IgE levels
  • "The itch that rashs"
  • Chronic results in thickening
  • Sub-acute results in crusting, oozing, dryness

[edit] Chronic dermatitis: Seborrheic dermatitis

• Cutaneous characteristics of seborrheic dermatitis:
  • Erythematous papules characterized by greasiness and scaling
  • Distribution: symmetrical; sternum, axilla, scalp, naso-oral area, medial to scapulae, behind the ear
  • Characterized by increases sebaceous gland production of oil ("greasiness")
  • Infant form is called "cradle cap"
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• Non-cutaneous characteristics of seberrheic dermatitis:
  • HIV is a risk factor
  • Parkinsons results more frequently

• Clinical characteristics of seborrheic dermatitis:
  • Unknown cause
  • Pityrosporium species may be involved
  • Elevated frequency in AIDS and Parkinson disease

• Other images of seborrheic dermatitis:
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[edit] Chronic dermatitis: Stasis dermatitis

• Cutaneous characteristics of stasis dermatitis:
  • Erythematous, brown lesions with a sharp border, scaling, ulcerations, and crusting
  • Think ulcers; very difficult to treat
  • Edema
  • Fibrosis
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• Non-cutaneous characteristics of stasis dermatitis:
  • Peripheral venous disease
  • Hemosiderin abnormalities

[edit] Ichthyosis

• Cutaneous characteristics:
  • Fish skin with scaling, no erythema (lack of inflammation), and a white or brown coloration
  • Distribution: pectoral region, palms (hyperlinear), keratosis pilaris (rough bumps on the skin from an auto-dominant follicular disorder)
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• Non-cutaneous characteristics:
  • Potential for cancers

• Clinical characteristics of ichthyosis:
  • Genetics play an important role
    • Recall that keratosis pilaris is seen which is an auto-dominant follicular disorder

**Associated with internal disease

[edit] Superficial fungal infections

• Cutaneous characteristics of fungal infections:
  • Erythematous macules / patches with scaling
  • Tinea capitis / corporis