Dermatology Book



Aka: Psoriasis, Chronic Plaque Psoriasis, Guttate Psoriasis, Inverse Psoriasis, Flexural Psoriasis, Erythrodermic Psoriasis, Psoriatic Onychodystrophy, Psoriatic Nail Pitting, Psoriatic Onycholysis
  1. See Also
    1. Psoriatic Arthritis
  2. Epidemiology
    1. Bimodal peaks
      1. Young adulthood (ages 16 to 22 years old)
      2. Older age (late 50s)
    2. Prevalence: 1-2% of general population (U.S.)
    3. Men and women affected equally
  3. Pathophysiology
    1. Underlying genetic predisposition is common (30% with Psoriasis also have a first degree relative with Psoriasis)
      1. Pathogenesis is likely a combination between genetic predisposition and exposure to inciting triggers
    2. Autoimmune
      1. Viral Infection may precipitate process
      2. T-Cell-mediated autoimmune response
        1. Cytokines released and stimulate Keratinocytes
    3. Keratinocytes proliferate
      1. Epidermal cells proliferate too fast
        1. Cells cycle in 4 days instead of normal 3-4 weeks
      2. Abnormal keratin production
      3. Dermal inflammation
  4. Risk Factors: Associated environmental factors
    1. Suppressed by:
      1. Sun and humidity
    2. Provocative
      1. Injury to skin (Koebner Reaction)
      2. Streptococcal Pharyngitis
      3. Emotional upset
      4. Tobacco Use
      5. Obesity
      6. Alcohol Abuse
      7. HIV Infection (severe exacerbations)
      8. Medications
        1. Antimalarials
        2. Beta Blockers (e.g. Propranolol)
        3. Lithium
        4. NSAIDS
  5. Symptoms
    1. Pruritus is present in >80% of psorisis
      1. Psora is greek for itching
  6. Signs: Chronic Plaque Psoriasis (90% of cases)
    1. Description
      1. Widespread
      2. Sharply demarcated
      3. Bright pink, red or salmon-colored Plaques
      4. Overlying loose, white to silvery scale
    2. Location: Symmetrical
      1. Over joints and extensor surfaces of extremities
      2. On trunk, especially lower back and buttocks
      3. Palms and soles
      4. Scalp
      5. Umbilicus
    3. Signs suggestive of Psoriasis
      1. Auspitz Sign
      2. Koebner Phenomenon
  7. Signs: Associated findings
    1. Location specific signs
      1. Nail (Psoriatic Onychodystrophy)
        1. Lifetime Prevalence in up to 90% of Psoriasis patients (esp. Fingernails)
        2. Findings secondary to abnormal nail plate growth
          1. Nail Pitting
          2. Subungual hyperkeratosis
          3. Onycholysis
            1. Separation of distal edge of nail from nail bed
            2. Accumulation of crumbly subungual debris
      2. Gluteal cleft
        1. Eroded pinkness in crease
      3. Penis (genital involvement in 40% of cases)
        1. Pink Macules or Plaques on penis
      4. Large joints
        1. Hyperkeratosis over elbows, knees, and ankles
      5. Tongue
        1. Geographic Tongue (rare)
    2. Uncommon Clinical Variants
      1. Guttate Psoriasis (drop-like)
        1. Uncommon, accounting for only 2% of Psoriasis cases
        2. Typically affects younger patients, under age 30 years
        3. Trunk lesions are 1-10 mm Papules with fine scale
        4. Commonly occurs following Streptococcal Pharyngitis or Upper Respiratory Infection
      2. Inverse Psoriasis (flexural)
        1. Less scale present than in Plaque form
        2. Affects flexor surfaces (inframammary, axillary and inguinal folds)
        3. Affects perineal and intergluteal regions
      3. Palmoplantar Pustulosis (Pustular Psoriasis)
        1. Likely represents a distinct condition from Psoriasis
        2. Pustules on palms and soles without Plaques
        3. von Zumbusch variant causes severe, acute, life-threatening sub-type
      4. Erythrodermic Psoriasis (Erythroderma)
        1. Broad-spread generalized erythema
        2. Systemic symptoms are typically present
    3. Systemic Signs
      1. Psoriatic Arthritis
      2. Uveitis (up to 20% of Psoriatic Arthritis cases)
    4. Severe widespread Psoriasis systemic signs
      1. Benign Lymphadenopathy
      2. Fever, chills, and Hyperthermia
      3. Increased cardiac demand
      4. High output Heart Failure
      5. Increased Sedimentation Rate and Uric Acid
      6. Decreased Serum Albumin
      7. Iron Deficiency Anemia
  8. Differential Diagnosis
    1. Lichen Simplex Chronicus
    2. Nummular Eczema
    3. Seborrheic Dermatitis
    4. Tinea Corporis
    5. Group A Beta Hemolytic Streptococcus
      1. May present as Guttate Psoriasis in children
      2. Obtain ASO Titer and Throat Culture
  9. Associated Conditions (related to psoriatic medications)
    1. Inflammatory Bowel Disease (Crohns' Disease or Ulcerative Colitis)
      1. Risk increased 3.8 to 7.5x
    2. Celiac Disease
    3. Malignancy
      1. Squamous Cell Skin Cancer
        1. Risk increased 14x associated with PUVA in caucasians
      2. Lymphoma
        1. Risk increased 1.3 to 3x
    4. Major Depression
      1. Prevalence: 60% of Psoriasis patients
    5. Other associated conditions with increased risk
      1. Myocardial Infarction
  10. Management: Approach - Moderate Chronic Plaque Psoriasis
    1. Trunk and extensor surface involvement
      1. Initial and exacerbation therapy (<4 weeks only)
        1. Protocol 1: Steroid and Calcipotriene
          1. High potency Topical Corticosteroid each morning
          2. Calcipotriene applied every evening
        2. Protocol 2: Single agent
          1. High potency Topical Corticosteroid or
          2. Calcipotriene or
          3. Tazorotene (Tazorac)
      2. Long-term maintenance (beyond 4 weeks)
        1. Calcipotriene or
        2. Tazorotene (Tazorac)
    2. Flexor surface involvement
      1. Moderate Topical Corticosteroids (<4 weeks) or
      2. Tacrolimus or Pimecrolimus
    3. Scalp involvement
      1. Exacerbations
        1. Topical Corticosteroid (brief use)
        2. Example: Clobetasol 0.05% Shampoo
      2. Maintenance
        1. Anti-DandruffShampoo
        2. Examples: T-gel or selsun
    4. Adjuncts
      1. Lac-Hydrin or salicylic acid applied daily to soften Plaques
  11. Management: Approach - Severe Chronic Plaque Psoriasis
    1. Criteria
      1. Psoriasis refractory to above therapy
      2. Chronic Plaque Psoriasis involving >5-20% of body
      3. Comorbid Psoriatic Arthritis
      4. Involvement of hands, feet, face or genitalia
    2. Protocol usually managed by dermatology
      1. Use above topical agents
      2. See Ultraviolet light below
      3. See Systemic Agents below
  12. Management: General Measures
    1. Soak lesions to ease adherent scale removal
    2. Apply Lac-Hydrin or salicylic acid applied daily to Plaques (reduces Scaling and softens Plaques)
    3. Apply skin Emollients (e.g. vaseline, aquaphor)
      1. Apply after soaks
      2. Apply 20 minutes after Corticosteroid application to boost steroid effect (similar to Occlusion)
    4. Consider Emollient only periods of steroid holiday
  13. Management: Topical Preparations
    1. Topical Corticosteroids
      1. Consider limiting potent steroids to 2-4 weeks at a time
        1. Then rotate to lower potency steroids or decrease application frequency (e.g. twice weekly)
        2. Consider Emollient only periods until reexacerbation
      2. High Potency Topical Steroids (Class 2 to 5, usually indicated)
        1. Very high potency: e.g. Clobetasol (Temovate)
        2. High potency: e.g. Fluocinonide (Lidex)
      3. Low Potency Topical Steroids (e.g. Hydrocortisone 2.5%)
        1. Face
        2. Genitalia
        3. Forearms
        4. Intertriginous regions
        5. Maintenance Therapy
    2. Vitamin D based topicals (Calcipotriene, Calcitriol)
      1. Indicated for moderate Psoriasis involving 5-20% of body surface area
      2. Used alone or in combination with Phototherapy or Topical Corticosteroids
      3. Risk of Hypercalcemia in high dose exposure and Renal Insufficiency
      4. Preparations
        1. Calcipotriene (Dovonex)
        2. Calcitriol (Vectical)
          1. May be less irritating than Calcipotriene (Dovonex)
    3. Retinoid based topicals: Tazarotene (Tazorac)
      1. More irritating than Calcipotriene
      2. As effective as Corticosteroids, but with longer disease-free periods
      3. Do not use in pregnancy (Teratogenic)
    4. Immunosuppressant based topicals (Tacrolimus, Pimecrolimus)
      1. Indications
        1. Effective in facial and intertriginous Psoriasis (due to less skin atrophy than with Corticosteroids)
      2. Agents
        1. Tacrolimus 0.1% cream
        2. Pimecrolimus 0.1% cream
      3. Efficacy
        1. Effective in facial and intertriginous Psoriasis
        2. Lebwohl (2004) J Am Acad Dermatol 51:723-30 [PubMed]
      4. Adverse effects
        1. Risk of skin cancer and Lymphoma (especially in combination with UV Light Therapy)
    5. Adjunctive agents in combination with above
      1. Topical Salicylic Acid (Keratolytic Agent)
    6. Novel newer agents (expensive and unclear efficacy in comparison with established agents)
      1. Aryl Hydrocarbon Receptor Agonists (AhR Agonists)
        1. Roflumilast (Vtama) 1% Cream applied once daily
          1. Approved only for adults
          2. Considered safe for longterm use, including in regions of thin skin (e.g. groin, face)
          3. Adverse effects include Folliculitis in up to 20% of patients
      2. Phosphodiesterase 4 Inhibitors (PDE4 Inhibitors)
        1. Similar to Eucrisa, a PDE4 Inhibitor indicated in Eczema
        2. Tapinarof (Zoryve) 0.3% cream applied once daily
          1. Approved for age 12 and older
          2. Considered safe for longterm use, including in regions of thin skin (e.g. groin, face)
          3. Adverse effects include Diarrhea, Headache
      3. References
        1. (2022) Presc Lett 29(10): 58-9
    7. Poorly tolerated topicals (Calcipotriene has largely replaced these)
      1. Historically used with UVB light exposure
      2. Anthralin 0.1% (Anthra-Derm)
        1. As effective as Calcipotriene
        2. Adverse effects include perilesional erythema, skin staining, burning Sensation
        3. Avoid applying to face or other sensitive areas, and avoid applying for longer than 2 hours
      3. Coal Tar (e.g. Zetar)
        1. Effective and inexpensive
        2. Consider in patients who can not afford other options
        3. More effective than Calcipotriene
        4. Avoid in pregnancy and Lactation
        5. Adverse effects include Folliculitis, Contact Dermatitis, Phototoxic Dermatitis
  14. Management: Ultraviolet Light
    1. Risk of non-Melanoma skin cancer
    2. Protocols
      1. Ultraviolet B exposure alone
      2. Ultraviolet A exposure with psoralen (PUVA)
        1. Increased risk of non-Melanoma skin cancer
  15. Management: Systemic agents (most are higher risk) for moderate to severe Psoriasis
    1. Immunosuppressants
      1. Methotrexate
        1. Typically trialed as a first-line systemic agent (unclear efficacy)
        2. See Methotrexate for monitoring guidelines
        3. Folic Acid 1-5 mg daily (except for the day Methotrexate is taken) reduces adverse effects
      2. Cyclosporine
        1. Used as a rescue agent for flares in refractory cases for up to 12 weeks
        2. Monitor Blood Pressure and Renal Function (see Cyclosporine for monitoring)
      3. Etretinate
    2. Systemic Retinoids (oral)
      1. Acitretin (Soriatane)
        1. Slow onset over 3-6 months
        2. Most effective in combination with Phototherapy (and Corticosteroids, Calcipotriene)
        3. Similar adverse effects to Accutane
          1. Highly Teratogenic (do not use in pregnancy)
          2. Teratogenicity lasts for 3 years after the medication has been used
    3. Phosphodiesterase Inhibitor (Type 4)
      1. Apremilast (Otezla)
        1. Available as of 2015 in U.S.
        2. Does not require lab monitoring
        3. Expensive ($1875/month)
        4. Adverse effects include Diarrhea, Nausea, as well as weight loss and depression
        5. Avoid use with Strong Cytochrome P450-3A4 Inducers (e.g. Rifampin, Carbamazepine)
    4. Biologic agents (Cost from $10k to >$20k/year)
      1. Tumor Necrosis Factor (tnf) receptor blockers
        1. Adalimumab (Humira)
          1. Preferred TNF agent
        2. Ustekinumab (Stelara)
          1. Preferred TNF agent
        3. Etanercept (Enbrel)
          1. Less effective than Adalimumab (Humira) and Ustekinumab (Stelara)
          2. Leonardi (2003) N Engl J Med 349:2014-22 [PubMed]
        4. Infliximab (Remicade)
          1. More adverse effects than other TNF agents
          2. Winterfield (2004) Dermatol Clin 22:437-47 [PubMed]
        5. Brodalumab (Siliq)
          1. Increased Suicide Risk
        6. Guselkumab (Tremfya)
      2. Other mechanisms
        1. Alefacept (Amevive)
        2. Efalizumab (Raptiva)
          1. Lebwohl (2003) N Engl J Med 349:2004-13 [PubMed]
        3. Cosentyx (secukinumab)
          1. New Interleukin-17a blocker available in U.S. in 2015
    5. Experimental
      1. Thiazolidinedione (Actos)
        1. Appears effective in Psoriasis even in non-diabetics
        2. Only small trials support to date
        3. Ellis (2000) Arch Dermatol 136(5):609-16 [PubMed]
  16. References
    1. (2015) Presc Lett 22(3): 16
    2. Hsu (2012) Arch Dermatol 148(1): 95-102 [PubMed]
    3. Luba (2006) Am Fam Physician 73:636-46 [PubMed]
    4. Mason (2002) Br J Dermatol 146:351-64 [PubMed]
    5. Menter (2008) J Am Acad Dermatol 58(5): 826-50 [PubMed]
    6. Teichman (2018) Am Fam Physician 97(2): 102-10 [PubMed]
    7. Weigle (2013) Am Fam Physician 87(9): 626-33 [PubMed]
    8. Elmets (2021) J Am Acad Dermatol 84(2):432-70 +PMID: 32738429 [PubMed]

Psoriasis (C0033860)

Definition (MEDLINEPLUS)

Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. You usually get the patches on your elbows, knees, scalp, back, face, palms and feet, but they can show up on other parts of your body. Some people who have psoriasis also get a form of arthritis called psoriatic arthritis.

A problem with your immune system causes psoriasis. In a process called cell turnover, skin cells that grow deep in your skin rise to the surface. Normally, this takes a month. In psoriasis, it happens in just days because your cells rise too fast.

Psoriasis can be hard to diagnose because it can look like other skin diseases. Your doctor might need to look at a small skin sample under a microscope.

Psoriasis can last a long time, even a lifetime. Symptoms come and go. Things that make them worse include

  • Infections
  • Stress
  • Dry skin
  • Certain medicines

Psoriasis usually occurs in adults. It sometimes runs in families. Treatments include creams, medicines, and light therapy.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Definition (NCI) An autoimmune condition characterized by red, well-delineated plaques with silvery scales that are usually on the extensor surfaces and scalp. They can occasionally present with these manifestations: pustules; erythema and scaling in intertriginous areas, and erythroderma, that are often distributed on extensor surfaces and scalp.(NICHD)
Definition (NCI_NCI-GLOSS) A chronic disease of the skin marked by red patches covered with white scales.
Definition (MSH) A common genetically determined, chronic, inflammatory skin disease characterized by rounded erythematous, dry, scaling patches. The lesions have a predilection for nails, scalp, genitalia, extensor surfaces, and the lumbosacral region. Accelerated epidermopoiesis is considered to be the fundamental pathologic feature in psoriasis.
Definition (CSP) common polygenetically determined, chronic, squamous dermatosis characterized by rounded erythematous, dry, scaling patches.
Concepts Disease or Syndrome (T047)
MSH D011565
ICD10 L40, L40.9
SnomedCT 156369008, 200978009, 156371008, 267851002, 200961000, 9014002
LNC LA15165-6
English Psoriases, Psoriasis, PSORIASIS, Psoriasis NOS, Psoriasis unspecified, Psoriasis, unspecified, psoriasis (diagnosis), psoriasis, Psoriasis [Disease/Finding], psoriases, psoriasi, Psoriasis NOS (disorder), Psoriasis unspecified (disorder), Psoriasis (disorder), Psoriasis, NOS
French PSORIASIS, Psoriasis
Portuguese PSORIASE, Psoríase
Spanish PSORIASIS, psoriasis no especificada (trastorno), psoriasis, SAI, psoriasis, SAI (trastorno), psoriasis no especificada, psoriasis (trastorno), psoriasis, soriasis, Psoriasis
German PSORIASIS, Psoriasis, nicht naeher bezeichnet, Psoriasis, Schuppenflechte
Japanese 乾癬, カンセン
Swedish Psoriasis
Czech lupénka, psoriáza, Psoriáza
Finnish Psoriaasi
Korean 건선, 상세불명의 건선
Polish Łuszczyca
Hungarian Psoriasis
Norwegian Psoriasis
Dutch Psoriasis, niet gespecificeerd, psoriasis, Psoriasis
Italian Psoriasi
Derived from the NIH UMLS (Unified Medical Language System)

Guttate psoriasis (C0343052)

Concepts Disease or Syndrome (T047)
ICD10 L40.4
SnomedCT 156371008, 267851002, 37042000
Dutch gespikkelde psoriasis, guttata; psoriasis, psoriasis; guttata, Psoriasis guttata
French Psoriasis en gouttes
Italian Psoriasi guttata
Portuguese Psoríase em gotas
Spanish Psoriasis gutata, psoriasis en gotas (trastorno), psoriasis en gotas, psoriasis guttata, soriasis en gotas, soriasis guttata
Japanese 滴状乾癬, テキジョウカンセン
Czech Psoriasis guttata
Korean 물방울 건선
English psoriasis guttata, psoriasis guttate, guttate psoriasis (diagnosis), guttate psoriasis, Guttate psoriasis, Psoriasis guttata, Guttate psoriasis (disorder), guttata; psoriasis, psoriasis; guttata
Hungarian Psoriasis guttata
German Psoriasis guttata
Derived from the NIH UMLS (Unified Medical Language System)

Flexural psoriasis (C0343053)

Concepts Disease or Syndrome (T047)
ICD10 L40.8
SnomedCT 238600001, 25847004
Dutch psoriasis inversa, flexurale psoriasis, gewrichtsplooi; psoriasis, psoriasis; gewrichtsplooi
French Psoriasis aux plis de flexion, Psoriasis inversé
German Psoriasis inversa, inverse Psoriasis
Italian Psoriasi di piega, Psoriasi inversa
Portuguese Psoríase das superfícies de flexão, Psoríase inversa
Spanish Psoriasis inversa, Psoriasis en superficie flexora, psoriasis de los pliegues (trastorno), psoriasis de los pliegues
Japanese 逆型乾癬, 屈側性乾癬, クッソクセイカンセン, ギャクガタカンセン
Czech Flexurální psoriáza, Inverzní psoriáza
English inverse psoriasis, Inverse psoriasis, Flexural psoriasis, psoriasis inverse, psoriasis inverse (diagnosis), Flexural psoriasis (disorder), flexural; psoriasis, psoriasis; flexural
Hungarian Flexuralis psoriasis, Inverz psoriasis
Derived from the NIH UMLS (Unified Medical Language System)

Chronic small plaque psoriasis (C0406317)

Concepts Disease or Syndrome (T047)
ICD10 L40.0
SnomedCT 200965009, 402308005
English plaque psoriasis, Discoid psoriasis, Nummular psoriasis, Plaque psoriasis, Chronic small plaque psoriasis (disorder), Chronic small plaque psoriasis, Plaque psoriasis (disorder), en plaques; psoriasis, nummular; psoriasis, psoriasis; nummular, psoriasis; plaque
Spanish Psoriasis en placas, placa de psoriasis (trastorno), placa de psoriasis, placa de soriasis, psoriasis crónica en pequeñas placas (trastorno), psoriasis crónica en pequeñas placas, psoriasis discoide, psoriasis numular, soriasis discoide, soriasis numular
Portuguese Psoríase em placas
Italian Psoriasi a placche
German Plaque-Psoriasis
French Psoriasis en plaques
Dutch plaque psoriasis, en plaques; psoriasis, nummularis; psoriasis, psoriasis; en plaques, psoriasis; nummularis
Czech Ložisková lupénka
Hungarian Plakk psoriasis
Japanese キョクメンガタカンセン, 局面型乾癬
Derived from the NIH UMLS (Unified Medical Language System)

Psoriatic nail pitting (C0406324)

Concepts Disease or Syndrome (T047)
SnomedCT 238606007
English Psoriatic nail pitting, Psoriatic nail pitting (disorder)
Spanish punteado ungueal psoriásico (trastorno), punteado ungueal psoriásico
Derived from the NIH UMLS (Unified Medical Language System)

Psoriatic onycholysis (C0406325)

Concepts Disease or Syndrome (T047)
SnomedCT 238607003
English Psoriatic onycholysis, Psoriatic onycholysis (disorder)
Spanish onicólisis psoriática (trastorno), onicólisis psoriática
Derived from the NIH UMLS (Unified Medical Language System)

Erythrodermic psoriasis (C0748052)

Concepts Disease or Syndrome (T047)
SnomedCT 56210000, 200977004
English Exfoliative derm due psoriasis, psoriasis erythrodermic, erythrodermic psoriasis, Erythrodermic psoriasis, Exfoliative dermatitis due to psoriasis, Erythrodermic psoriasis (disorder), Exfoliative psoriasis, Psoriatic erythrodermia
French Psoriasis érythrodermique, Erythrodermie psoriasique
Italian Psoriasi eritrodermica, Eritrodermia psoriasica
Portuguese Psoríase eritrodérmica, Eritrodermia psoriática
Spanish Psoriasis eritrodérmica, Eritrodermia psoriásica, psoriasis eritrodérmica, soriasis eritrodérmica (trastorno), soriasis eritrodérmica, psoriasis eritrodérmica (trastorno)
Dutch psoriatische erythrodermie, erytrodermische psoriasis
Japanese 乾癬性紅皮症, カンセンセイコウヒショウ
Czech Psoriatická erytrodermie, Erytrodermní psoriáza
Hungarian Psoriasisos erythrodermia, Erythrodermiás psoriasis
German Psoriasis erythrodermica
Derived from the NIH UMLS (Unified Medical Language System)

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