Answer of Dermatopathology Case 77

Psoriasis

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Abstract:

Scalp psoriasis: an overview of the disease and available therapies.J Drugs Dermatol. 2010 Aug;9(8):912-8.
The scalp is one of the regions of the body most commonly affected by psoriatic lesions. While the head represents only 10 percent of the body's surface area, the consequences of scalp psoriasis are disproportionate to the area, as it can be seriously debilitating and presents social and emotional distress to the affected individual. Scalp lesions are often well-demarcated and may have thick gray or white scale; patients with scalp psoriasis frequently complain of pruritus and shedding of scale. Current treatment modalities--including phototherapy, topical corticosteroids, topical vitamin D analogues and conventional systemic therapies--have produced unsatisfactory results for patients with moderate-to-severe scalp psoriasis due to difficulties in administration to the disease site, poor compliance, toxicity and inadequate long-term efficacy. The emergence of biologic therapies as an effective modality for the treatment of plaque psoriasis may provide another option for patients suffering from plaque psoriasis of the scalp.

Diagnosis of nail psoriasis: importance of biopsy and histopathology. Br J Dermatol.2005 Dec;153(6):1153-8.
BACKGROUND: Involvement of the nail is quite common in psoriasis and at times may be the sole diagnostic clue. However, the histopathology of nail psoriasis has not been adequately evaluated. A confirmation of the diagnosis is required in cases suspected to have nail psoriasis in order to plan long-term therapy.
OBJECTIVES: To assess the diagnostic significance and safety profile of nail biopsy in cases with nail psoriasis.
METHODS: Clinical and mycological features were studied in 42 patients with nail psoriasis. Of these, 22 patients gave consent for nail biopsies to be taken and the histopathological changes were assessed.
RESULTS: Males were affected more commonly (57%) with a peak incidence in the age group of 10-20 years (29%). Distal onycholysis, discoloration of nail plate, subungual hyperkeratosis and fine nail pitting were the predominant clinical features. In the 22 biopsies done, hyperkeratosis with parakeratosis (91%) was found to be the most common and hypergranulosis was the least common histological finding (36%). Clinicohistological correlation was possible only in 55% cases. Periodic acid-Schiff (PAS) staining was done for all biopsies.
CONCLUSIONS: Histopathological examination of nails is a valuable diagnostic aid, especially in the absence of skin lesions. Examination of the PAS-stained sections is necessary before making a histological diagnosis of nail psoriasis because onychomycosis and psoriasis may show similar histology.

Psoriasis triggered by mefloquine. Skinmed. 2010 Sep-Oct;8(5):301-2.
A 46-year-old Caucasian man living on the central Mediterranean island of Gozo (Malta) was started on mefloquine 250 mg once weekly before a trip to lower Egypt. He took his medication 1 week before starting his holiday and was advised to continue it for 4 weeks after returning. He did not take any other medication and enjoyed the holiday, which he initially intended to repeat in the near future. His medical history revealed a number of episodes of psoriasis for which he sought dermatologic advice. He had been given systemic therapy on at least one occasion, but the condition had been fairly quiescent for some time and he had not needed to consult a dermatologist for more than 4 years. Soon after the third tablet of mefloquine and effectively just after his return home to Gozo, the patient noticed that the psoriasis was "creeping back." He noted progressive deterioration in his skin problem but nevertheless finished the recommended course of therapy considering that "being sure about not developing malaria was far more important than a touch of psoriasis." The psoriasis worsened to the extent that he had taken off work for 2 weeks from his job as a self-employed carpenter at the time of referral. On examination, clearly there was a significant flare up of his psoriasis with severe involvement of the hands (Figure 1) and feet and less so over the rest of his body. He had been off work and matters were steadily getting worse in spite of topical treatment with a combination of calcipotriol-betamethasone ointment. Oral methotrexate 15 mg once weekly was commenced together with topical therapy with good results (Figure 2).

Increased Prevalence of Human Papillomavirus in Hairs Plucked From Patients With Psoriasis Treated With Psoralen-UV-A. Arch Dermatol. 2004 Mar;140(3):317-24.
BACKGROUND: Patients with psoriasis treated with psoralen-UV-A (PUVA) are at increased risk of skin cancer; however, the exact causes of this increased incidence are not well understood. It has been suggested that PUVA may increase expression of the tumorigenic agent human papillomavirus (HPV) in skin by directly stimulating virus replication, immune suppression, or both, thereby leading to skin cancer formation. OBJECTIVE: To determine whether HPV DNA prevalence in the skin is increased after long-term PUVA treatment. DESIGN: Screening for the presence of HPV sequences in DNA isolated from plucked body hairs of patients with psoriasis with a history of PUVA exposure and a history of skin cancer (group A), PUVA exposure and no history of skin cancer (group B), and no PUVA exposure and no history of skin cancer (group C). SETTING: University hospital.Patients and METHODS: Hair samples were obtained from 81 patients with psoriasis (56 men and 25 women; mean age, 52 years), including 16 in group A (mean number of PUVA exposures, 702), 35 in group B (mean number of PUVA exposures, 282), and 30 in group C. DNA was isolated from the hair samples and analyzed by polymerase chain reaction with the use of 2 nested primer systems specific for epidermodysplasia verruciformis-associated or related and genital or mucosal virus types, respectively. RESULTS: The rate of HPV DNA positivity was significantly higher in groups A (73% [11/15]) and B (69% [24/35]) than in group C (36% [10/28]) (A + B vs C, P =.009; chi(2) test; age adjusted).Conclusion The prevalence of HPV in the skin (hair follicles) is increased in patients with psoriasis who have a history of PUVA exposure.