Psoriasis – Common Sites, Types, Investigation and Treatment

Psoriasis Common Sites, Types, Investigation and Treatment

This is psoriasis part 2, Psoriasis part 1 -(psoriasis etiology, pathogenesis and clinical features)

Psoriasis comes from Greek word, meaning “itching condition” (psora “itch” + -sis “action, condition”).

Psoriasis common sites:

  1. Extensor  surface
  2. Scalp
  3. Nails
  4. Elbow
  5. Knee
  6. Sacral region

 Psoriasis types:

  1. Psoriasis vulgaris (Also called Plaque Psoriasis)


Fig: Psoriasis Vulgaris

Psoriasis vulgaris is the most common form of psoriasis. It affects 80 to 90% of people with psoriasis. Plaque psoriasis typically appears as raised areas of inflamed skin covered with silvery white scaly skin. These areas are called plaques.

 2. Guttate Psoriasis

Guttate Psoriasis

Fig: Guttate Psoriasis

Guttate psoriasis occurs mostly m patients under age 30. In this distinctive  form  of  psoriasis typical lesions  are  the  size  of  water  drops,  2  to  5 mm  in diameter.  Lesions  typically  occur  as  an  abrupt  eruption following  some  acute  infection,  such  as  a  streptococcal pharyngitis.

3. Inverse Psoriasis

Penis Inverse Psoriasis

Fig: Penis Inverse Psoriasis

This   form selectively and often exclusively involves folds, recesses, and flexor surfaces such as the ears, axillae, groins, inframammary folds, navel, intergluteal crease, penis, lips, and webspaces.

4. Pustular Psoriasis

Pustular Psoriasis

Fig: Pustular Psoriasis

The  onset  is  sudden,  with formation  of lakes  of  pus periungually,  on the palms,  and at the edge  of psoriatic plaques. Erythema occurs in the flexures before the generalized   eruption appear. This is followed by a generalized erythema and more pustules

  • Generalized

Generalized pustular psoriasis (GPP) usually covers the entire body and with pus-filled blisters rather than plaques.

  • Localized

5. Napkin psoriasis

Napkin Psoriasis

Fig: Napkin Psoriasis

Napkin psoriasis, or psoriasis in the diaper area, is characteristically seen in infants between two and eight months of age.

6. Nail Psoriasis

Nail Psoriasis

Fig: Nail Psoriasis

Psoriatic nails are a nail diseases. It is common in those suffering from psoriasis, with reported incidences varying from 10% to 78%. Elderly patients and those with psoriatic arthritis are more likely to have psoriatic nails.

 7. Psoriatic Arthropathy

Psoriatic Arthropathy

Fig: Psoriatic Arthopathy

Psoriatic arthritis is said to be a seronegative spondyloarthropathy and therefore occurs more commonly in patients with tissue type HLA-B27.

8. Exfoliative (Erythrodermic) Psoriasis

Erythrodermic Psoriasis

Fig: Erythrodermic Psoriasis

Patients with psoriasis may develop a generalized erythroderma.

Psoriasis Lab Investigation:

Skin Biopsy (Histopathology)

  1. Regular elongation of rete ridges
    Rete Ridges in Psoriasis
    Fig: Rete Ridges in Psoriasis
  2. Dilated Blood Vessels in the elongated dermal papillae
  3. Acanthosis
  4. Parakeratosis
  5. Munro Micro Abscess in the para keratotic horny layer
  6. Absence of granular Layer

Psoriasis Treatment:

Tropical 1st Line drug for psoriasis:

  1. Coal Tar
  2. Dithranol
  3. Calcipotriol (Vitamin D analogue)
  4. Corticosteroid (Cream/Ointment/Lotion)
  5. Keratolytic Agent (Salicylic acid – 2%, 3%, 5%, 6%)

(4 + 5 +6 are used in Bangladesh)

2nd Line drug for Psoriasis:

a)      UVB (Artificial UVB light is produced by fluorescent bulbs in broad- or narrow-band spectrums. Maximal effect is usually achieved at minimal erythemogenic doses (MED).  – 3 times/weekly

b)      PUVA (Psoralen and ultraviolet A phototherapy (PUVA) combines the oral or topical administration of psoralen with exposure to ultraviolet A (UVA) light. The mechanism of action of PUVA is unknown)

8 methoxypsoralin (10 mg Tablet), 3-4 tabs 2hrs before UVA – 3 times/weekly

Systemic Therapy of Psoriasis:

  1. Methotrexate (Tab MTX 2.5 mg) + Folic Acid (5 mg)

3 divided oral doses weekly – 12 hrs. Apart

Once weekly dose orally

Single weekly dose Subcutaneous Injection

  1. Oral Retinoid – 0.5 mg/Kg/day
  2. Cyclosporine – 3-5 mg/Kg/day for 4-8 weeks
  3. Antibiotic – Erythromycin, Azithromycin
  4. Analgesics and anti-inflammatory for Psoriatic Arthropathy

Psoriasis patient Advice:

Avoid – Precipitating factors such as trauma, sunlight, irritating drugs, stress and emotions

Biological Treatment of Psoriasis:

  1. Alefacept

Alefacept is used to control inflammation in moderate to severe psoriasis with plaque formation, where it interferes with lymphocyte activation.


Etanercept (trade name Enbrel) is a drug that treats autoimmune diseases by interfering with tumor necrosis factor (TNF; a soluble inflammatory cytokine) by acting as a TNF inhibitor.


Adalimumab (HUMIRA, Abbott) is the third TNF inhibitor, after infliximab and etanercept, to be approved in the United States. Like infliximab and etanercept, adalimumab binds to TNFα, preventing it from activating TNF receptors. HUMIRA (“Human Monoclonal Antibody in Rheumatoid Arthritis”)


Infliximab (INN; trade name Remicade) is a monoclonal antibody against tumour necrosis factor alpha (TNFα) used to treat autoimmune diseases.

Reference for my Psoriasis article:


2) Wikipedia


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