INTRODUCTION

Psoriasis is a chronic, immune-mediated skin disease characterized by systemic inflammation and hyperproliferation of keratinocytes, leading to erythematous, scaly plaques. Psoriasis is related to genetic factors, autoimmune disorders, and environmental factors such as infections, stress, and trauma. Psoriasis can affect individuals of various ages, particularly those between 15–20 and 55–60 years old.[1-3]

Assessing treatment efficacy is crucial for dermatologists, and one of the most widely used measures is the Psoriasis Area and Severity Index (PASI). PASI 75 refers to a 75% reduction in PASI score from baseline, indicating significant clinical improvement. It has become a key benchmark in evaluating the effectiveness of systemic therapies, including biologics and small-molecule drugs. Achieving PASI 75 is often associated with substantial symptom relief and improved quality of life for patients.[3-5]

CASE REPORT

A 26-year-old female, came to the Dermatology and Venereology Department of Haji Adam Malik General Hospital in Medan, Indonesia with chief complaint of itchy and scaly red plaques almost all over her body since 1 month ago. Initially, two years ago, the patient complained of red, itchy skin on both the left and right hands. One year ago, the red patches became more widespread and were accompanied by skin thickening all over the body. The patient consulted a dermatologist and was prescribed oral methylprednisolone, but the symptoms did not improve. One month ago, the red patches became even thicker and itchy across the entire body.

Dermatological examination showed that the lesions were multiple erythematous plaques with thick rough squama on the face, trunk, back, as well as both arms and legs (Figure 1). Based on the surface area of the involved skin, the body surface area (BSA) of the patient was 45%. Based on the intensity of the redness, thickness and scaling of the lesions, the measurement of Psoriasis Area and Severity Index (PASI) score of this patient was 21,8 that can be classified as moderate-to-severe psoriasis.

Figure 1. Multiple erythematous plaques with thick, rough squama on trunk, back, both arms and legs of the patient.

Laboratory results showed that hemoglobin 10.4 g/dL, leukocytes 10.150/mm3, erythrocytes 4.56 million/mm3, platelets 301.000/mm3, urea 13 mg/dL, and creatinine 0.55 mg/dL. Histopathological examination revealed that there were A stratified squamous epithelial lining is observed, showing regular acanthosis with elongated rete ridges and hyperkeratosis, while the structure and nuclear morphology remain within normal limits. There is also neutrophilic inflammatory cell infiltration in some areas of hyperkeratosis. In the subcorneal layer, thinning of the suprapapillary plate is noted. The stroma consists of fibrous connective tissue with lymphocytic inflammatory cell infiltration (Figure 2).

A close-up of a microscope slide Description automatically generated

Figure 2. A stratified squamous epithelial lining is observed, showing regular acanthosis with elongated rete ridges and hyperkeratosis, while the structure and nuclear morphology remain within normal limit. A neutrophilic inflammatory cell infiltration in some areas of hyperkeratosis. In the subcorneal layer, thinning of the suprapapillary plate

The patient was diagnosed with psoriasis vulgaris. The initial treatment of this patient was the combination of 2x2.5mg/week of oral methotrexate, loratadine 1x10mg, emollient 2x a day, desoksimetasone cr + salicylic acid 5% 2x a day for one month. The patient came back after one month and shows improvement with symptoms, but red skin with itching and scales is still present across the body, PASI Score reduce to 16,8. Patient was given the same therapy and patient was advised to return for a follow-up in one month. Follow up of the lesions after 2 months show erythematous plaques with thick rough squama on trunk, back, arms and legs have subsided and PASI Score reduce to 9,8 (Figure 3).

Figure 3. Follow up of the lesions after 2 months. There were improvements of the patient's condition, erythematous plaques have decreased.

DISCUSSION

Psoriasis vulgaris is primarily an immune-mediated condition with genetic and environmental influences, where the activation of keratinocytes and immune cells leads to excessive keratinocyte proliferation. The predilection sites of psoriasis include extensor surfaces such as the elbows and knees, the lumbosacral region, the buttocks, and the genital area. Psoriasis can occur at any age, with a bimodal age distribution, typically appearing between 18–39 years and 50–69 years. Other literature suggests peak onset ages of 16–22 years and 57–62 years. In addition to genetic factors, environmental triggers such as trauma, infections, stress, medications, and immune system dysfunction contribute to the autoimmune pathogenesis of psoriasis.[6-9]

Histopathological examination plays a crucial role in confirming the diagnosis and understanding the underlying pathophysiology of the disease. The histopathological features of psoriasis include parakeratosis, often accompanied by hyperkeratosis, acanthosis, elongation of rete ridges, and lengthening of the dermal papillae, along with Munro microabscesses in the epidermis, surrounded by lymphocyte and monocyte infiltration.[2,10,11] The histopathological findings in this case are consistent with the literature, showing a stratified squamous epithelial lining with regular acanthosis, elongated rete ridges, hyperkeratosis, and normal nuclear structure and morphology.

Additional laboratory tests may reveal leukocytosis, anemia, increased erythrocyte sedimentation rate (ESR), and electrolyte imbalances.[3,12] In this case, a complete blood count and kidney function test were performed, revealing anemia while kidney function remained within normal limits.

According to literature, the PASI (Psoriasis Area and Severity Index) score is used to assess the severity of psoriasis lesions. Fredrickson and Pettersson first introduced the PASI scoring system, which is now widely used in clinical evaluation and treatment response assessment. The PASI score ranges from 0 to 72 and is categorized as mild (PASI <5), moderate (PASI 5–10), and severe (PASI >10).[13,14] The management of psoriasis vulgaris aims to control the disease and achieve remission rather than a cure. Treatment options are tailored based on body surface area (BSA) involvement. If the lesion coverage exceeds 30% of BSA, a combination of topical therapy, phototherapy, and systemic therapy is recommended.[15]

In this case, the patient was treated with methotrexate, loratadine, desoximetasone 0.25% cream + 3% salicylic acid, and a moisturizer. Methotrexate, an immunosuppressive drug, works by inhibiting the enzyme dihydrofolate reductase. It is used for moderate to severe psoriasis and psoriatic arthritis due to its cytostatic and anti-inflammatory properties, though its safety profile is limited. It is administered orally with dose titration of 5–7.5 mg or 15–20 mg per week. Side effects may include hepatotoxicity, nausea, vomiting, diarrhea, and fatigue. Folic acid supplementation can help reduce methotrexate-related side effects.[2,16,17]

The patient was diagnosed with severe psoriasis vulgaris based on a PASI score of 21.8. The patient's PASI score showed reduction, indicating a good therapeutic response. After 2 month, the PASI score was calculated at 9.8, reflecting a reduction of more than 75%. Psoriasis treatment is considered successful when PASI 75 is achieved, meaning a 75% reduction in the PASI score. Conversely, it is considered unsuccessful if PASI 50 is not reached, indicating a reduction of less than 50% in the PASI score.[18,19]

Topical therapies include emollients (moisturizers), glucocorticoids, and vitamin D analogs as first-line treatment. Second-line options include tazarotene, salicylic acid, dithranol, and coal tar. Phototherapy, narrowband UVB (NB-UVB) and broadband UVB are first-line options, while psoralen plus UVA (PUVA), excimer laser therapy, and climatotherapy serve as second-line treatments.[17,20]

CONCLUSION

This case underscores the significance of PASI 75 as a critical treatment objective in both clinical research and routine practice, serving as a guide for dermatologists in optimizing patient management.

DECLARATIONS

The authors wish to express their gratitude to the patient who participated in this study and provided informed consent, as well as to the Faculty of Medicine at the University of North Sumatra, Medan.

CONSENT FOR PUBLICATION

The Authors agree to be published in Journal of Society Medicine.

FUNDING

None

COMPETING INTERESTS

The authors declare that there are no conflicts of interest.

AUTHORS’ CONTRIBUTIONS

All authors made substantial contributions to the work reported in this manuscript. They participated in drafting, revising, or critically reviewing the article. Furthermore, they approved the final version for publication, concurred on the journal for submission, and accepted responsibility for all aspects of this work.

ACKNOWLEDGMENTS

None

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