By Dr Hanish Babu, MD, Dermatologist & Venereologist, City Medical Centre Ajman and Cosmolaser Medical Centre, Sharjah, UAE.
COMMON PRESENTATIONS OF PSORIASIS
Psoriasis signs and symptoms vary according to the morphology, stage and anatomical site of involvement of the psoriasis rashes, which are typically scaly plaques on a red base of skin.
Psoriasis is characterised by the development of erythematous (reddish), well defined, dry, scaly, papules and plaques of sizes ranging from a pin head to palm sized or larger. Lesions have a full rich red (salmon) color in the skin of Caucasians. Rarely, lesions on the legs or trunk may show a violaceous or bluish hue.
Psoriasis usually begins as small, erythematous, scaly papules that gradually enlarge to form well demarcated, raised, erythematous plaque with a scaly surface.
The scales in psoriasis are typically silvery white, dry, brittle and arranged in a lamellated fashion. This silvery white color is due to refraction of light through the air trapped in between the scales. The upper scales fall off in large quantities, while the lower layers of scales are firmly fixed.
Gentle scrapping of the surface of a psoriasis plaque with a glass slide will remove the loosely attached scales and reveal a shiny surface peppered with fine bleeding points. These bleeding points represent the dilated and tortuous capillary blood vessels in the papillary dermis, one of the characteristic pathological events taking place in psoriasis affected skin. This sign is known as Auspitz sign, which is a diagnostic sign of psoriasis.
The number of lesions in psoriasis may be a few or numerous. When multiple, they are arranged in a symmetrical fashion on the body.
The commonest sites for psoriasis are the extensor surfaces of the elbows and knees, low back (sacrum), and the scalp, but any part of the body may be involved.
Nail and joints may also be involved in psoriasis. Progressive painful joint swelling is seen in 10-30% of psoriasis patients.
Another characteristic of psoriasis is the Koebner phenomenon, whereby, new psoriasis lesions appear on areas of skin injury. The injury should reach the level of dermis for the Koebner phenomenon to appear. Superficial scratches involving the epidermis alone will not produce new psoriatic rashes.
Psoriasis derived its name from Sora (Gr), meaning itching. Itching is a prominent symptom in most cases, but varies greatly in intensity from case to case. Some patients do not experience itching at all. In the eruptive stage, when new lesions appear and the present ones progressively enlarge, a warm, burning sensation may be felt by the patient.
Clinical Types of Psoriasis
Depending upon distinct morphological and anatomical characteristics, psoriasis may be divided into different clinical types.
Depending upon the sites of involvement, psoriasis may be classified as scalp psoriasis, trunk psoriasis, flexural psoriasis, palmo-plantar psoriasis, psoriasis glans and nail psoriasis.
Common morphological clinical types of psoriasis are: guttate psoriasis, common plaque psoriasis, inverse or flexural psoriasis, pustular psoriasis and erythrodermic psoriasis.
Guttate Psoriasis is a special variant which primarily occurs in children and young people following a streptococcal throat infection. Drop-like, scaly patches appear on the entire body. In many cases, the condition disappears by itself after a few weeks or months. This type of psoriasis responds very well to systemic antibiotics.
Common Plaque Psoriasis
Plaque psoriasis is the commonest type of psoriasis, also known as psoriasis vulgaris, occurring in about 80% of psoriasis patients. Common plaque psoriasis usually begins as small, erythematous, scaly papules that gradually enlarge to form well demarcated, raised, erythematous plaque with a scaly surface.
Inverse or Flexural Psoriasis
This type of psoriasis occurs in skin folds (flexures). Red, itchy plaques appear in the armpits, under the breasts, on the stomach, in the groin or on the buttocks. The plaques are often infected by the yeast-like fungus candida albicans. Scales are usually absent in inverse psoriasis.
Psoriasis of the nail often manifests itself as small indentures in the nails. These are known as nail pits. Nail pits , though, is not a feature of psoriasis alone, many other skin conditions like alopecia areata can be associated with nail pits.
When the nail involvement is severe, the nail thickens and crumbles away. Nail involvement is most common when psoriatic joint (psoriatic arthritis) involvement is present.
Psoriasis of the Scalp
Psoriasis of the scalp can be difficult to distinguish from a severe case of dandruff or seborrheic dermatitis, and sometimes the two occur simultaneously. Thick scaly plaques localised to certain areas are typical of psoriasis scalp.
Pustular psoriasis is a rare variant where the inflammation is so severe that, in addition to the usual lesions, blisters or pustules containing fluid appear on the skin. This can be localised to the palms and soles or generalised, spreading all over the body
Erythrodermic psoriasis is the most severe form of psoriasis, which resembles a bad case of severe sunburn with redness, scaling and swelling of the skin all over the body.
In around 10 to 30% psoriasis patients, a debilitating joint disease, known as Psoriatic Arthritis may develop. It causes inflammation in and around the joints and affects an estimated 28 million psoriasis patients. People with psoriatic arthritis experience progressive joint pain and swelling, which is often coupled with scaly, red skin lesions on other areas of the body.
Clinical Types of Psoriasis According to Activity
Acute eruptive: This is the guttate variety which suddenly appears all over the body
Chronic progressive: The common plaque psoriasis, also known as psoriasis vulgaris. This gradually progress in size and number.
Chronic stationary :When the psoriasis lesions remain stationary without increasing in size and with a dull red colour and minimal scaling, this is a stationary stage. This stage usually precedes the regressive stage.
Chronic regressive: With or (sometimes)without treatment, psoriasis lesions gradually become thin, scaling reduces, the red color changes from dull red to violaceous and gradually fade. In those who have used steroids or ultraviolet radiation, a hypopigmented (whitish) ring known as Woronoff’s ring may be seen surrounding the lesion.
Choice of treatment differs for each of these types of psoriasis.
Read more about Psoriasis:
- What are the Triggers of Psoriasis?
- Psoriasis Different Types Classification
- How to Treat Scalp Psoriasis
The information given in this article is for educational purpose only so that patients are aware of the options available for diagnosis and treatment of common skin, hair and nail diseases. No diagnosis should be made or treatment undertaken without first consulting your dermatologist. If you do so, the author will not be responsible for any consequences. The images provided are for illustration purpose only and should not be reproduced without the consent of the author.
About the Author of Skin Care Tips from Dermatologist: Dr Hanish Babu, MD
Dr Hanish Babu, MD is a dermatologist with more than 3 decades of experience in treating skin and sexually transmitted diseases in UAE and India. He has been practicing in UAE since last 22 years. He is a respected speaker during the Continuing Medical education Programmes for doctors, medical students and paramedical staff and is also a Stress Management Trainer. He organises group therapy sessions for patients with psoriasis, eczema and vitiligo.
He is available for consultation at Cosmolaser Medical Centre in Samnan, Sharjah (06 5678 200) from 10 am – 2 pm and at City Medical Centre, Al Bustan, Ajman (06-7 441 882) from 4.30 pm – 9.30 pm.
Visit his personal website dr-hanishbabu.com for more details and for educational articles on Skin, hair, nail and sexually transmitted diseases. Click here to Book an Appointment with dermatologist Dr Hanish Babu, MD