Understand psoriasis

Psoriasis (also called plaque psoriasis) is a common chronic skin inflammatory disease. Most people with psoriasis have recurring thick, red skin with flaky patches on the scalp, face, trunk, and limbs. Psoriasis is currently incurable. Skin lesions may be very itchy and uncomfortable, and unpleasant in appearance, which sometimes are mistaken as an infectious skin disease by the public. These cause tremendous psychological stress and social impact, and affect the quality of life of the patients. Some psoriasis patients also have psoriasis arthritis that leads to joint inflammation and swelling, and sometimes nail disease causing nail deformity.

In addition to skin and joint symptoms, recent studies have also revealed that psoriasis patients are more susceptible to comorbid diabetes, hypertension, hyperlipidemia, cardiovascular disease, and other internal illnesses. Therefore, apart from receiving treatment for skin lesion, psoriasis patients must undergo examination for hypertension, high blood cholesterol, and high blood sugar. Treatment is crucial if any of these conditions are present.

Causes of psoriasis

Heredity: If a parent has psoriasis, a child has an increased chance of developing it. But it is not 100%.

External injury: skin injury, scratch, rubbing, or surgical wound may trigger psoriasis.

Infection: Streptococcal throat infection may trigger guttate psoriasis lesions.

Stress: Around 30-40% of the patients report that symptoms worsen in stressful times.

Medication: Steroid, antimalarial drug, some antihypertensives, and lithium may trigger the onset of psoriasis.

Hormones: Both puberty and menopause seem to trigger psoriasis, but some people’s conditions improve during pregnancy.

Clinical presentation of psoriasis

Psoriasis is a common chronic skin inflammatory and keratosis disease. It is a skin disease and a systemic condition. Additional to skin symptoms, 40% of the patients have comorbid arthritis. They are also at increased risk of hyperlipidemia, metabolic syndrome, obesity, cardiovascular disease, diabetes, and depression.

Common psoriasis

Also called plaque psoriasis

Plaque psoriasis is the most common form, affecting 90% and above of patients with psoriasis.

Clinical presentation: Characterized by red patches with a well-defined border, and covered with flaky white or silver scale.

Commonly affects the scalp, behind the ears, on the elbows, knees, hands, feet, trunk, and nails.

Scalp psoriasis and seborrheic dermatitis of the scalp can be difficult to differentiate

Flares of psoriasis on the hands and feet may be difficult to distinguish from eczema. Lesions on the trunk sometime appear similar to chronic eczema. Nail psoriasis is commonly misdiagnosed as tinea pedis.

Guttate psoriasis

Lesions appear similar to those of plaque psoriasis, which presents as small (0.1-1.5 cm in diameter) lesions usually less than 1 cm in diameter. It is more common in children and younger adults after streptococcal infection of the upper respiratory tract. Guttate lesions usually appear quickly on the trunk and limbs and can number in the hundreds.

Erythrodermic psoriasis or psoriatic erythroderma

The entire surface of the body becomes red with severe scaling.

Patients are prone to develop lower limb edema, fever, systemic symptoms, and abnormal heart and liver functions.

Pustular psoriasis

Appearance of sterile yellow pustules over red plaques, and may cause fever and exhaustion.

Typically localized to the palms and soles or to the fingertips. The generalized type affects the skin of the entire body.

Understand psoriatic arthritis

Around 20% of psoriasis patients are afflicted with psoriatic arthritis with the presence of psoriasis precedes the onset of psoriatic arthritis. The severity of psoriasis skin disease may not correlate with the severity of psoriatic arthritis. Patients may display minimal skin lesions and have severe joint condition. The cause of the disease is currently unknown.

Clinical presentation

1. Multiple symmetric psoriatic arthritis: affects the same joints on both sides of the body in symmetric pairs.

2. Asymmetric arthritis: it is the most common form and effects less joints. Affected joints may have inflamed tendons, causing enlarged digits.

3. Distal interphalangeal predominant (the joint closest to the nail): This type of psoriatic arthritis accounts for 5% and is often accompanied with nail changes.

4. Spondylitis: presented with chronic pain of the neck, lower back, or spinal vertebrae. Some have affected spinal vertebrae and some to the sacroiliac joints of the pelvis with peripheral arthritis.

5. Arthritis mutilans: Fewer psoriatic arthritis patients are affected by arthritis mutilans, a severe, deforming form of the disease.