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Chronic erythematous rash and lesions on trunk and limbs
Published in Richard Ashton, Barbara Leppard, Differential Diagnosis in Dermatology, 2021
Richard Ashton, Barbara Leppard
The word pityriasis means ‘bran-like’ and here means a scaly rash; versicolor means different colours. Pityriasis versicolor is a scaly rash of different colours. In different individuals it may be white, orange-brown or dark brown. The lesions are small, less than 1 cm in diameter, usually round and always scaly when scratched. Some may join together to form larger lesions or confluent plaques. It is a disease of young adults and occurs predominantly on the upper trunk. It is due to an infection with a yeast, Pityrosporum orbiculare, which we all have on our skin as a harmless commensal. Under certain conditions, the yeast produces hyphae and becomes pathogenic. It is then known as Malassezia globosa. The depigmentation is due to inhibition of tyrosinase by dicarboxylic acids produced by the pityrosporum yeast leading to suppression of melanin production.
Psoriasis and lichen planus
Published in Ronald Marks, Richard Motley, Common Skin Diseases, 2019
Pityriasis rubra pilaris is an uncommon skin disorder of unknown cause, which often has a superficial resemblance to psoriasis as it is characterized by redness and scaling patches, but has a distinctive natural history, histological appearance and a distinctive component of follicular involvement.
Skin disorders causing post-inflammatory hypopigmentation
Published in Electra Nicolaidou, Clio Dessinioti, Andreas D. Katsambas, Hypopigmentation, 2019
Polytimi Sidiropoulou, Dimitrios Sgouros, Dimitris Rigopoulos
Pityriasis alba (PA), a common benign condition, typically occurs during childhood and adolescence, affecting 1% of the general and 9.9% of the pediatric population. Although its pathogenesis remains unknown, it is included among PIH disorders. Excessive sun exposure, skin dryness, and atopic predisposition are strongly implicated in the development of PA. Clinically, the condition is characterized by ill-defined, round to oval, slightly scaly macules and patches with mild to moderate hypopigmentation. The lesions vary in size from 0.5 to 3 cm, but larger lesions can also occur. The face, especially the malar region, is the most frequent site of involvement, but lesions can occasionally develop on the neck, trunk, and extremities. This dermatosis is usually asymptomatic, but some patients complain of itching and burning. Under Wood's lamp examination, the lesions are enhanced. Histopathology of the affected skin reveals subacute spongiotic dermatitis along with reduced numbers of active melanocytes and a decrease in the number and size of melanosomes. Topical corticosteroids may be beneficial, but emollients seem to be equally effective. Recent data reported perfect results with topical calsineurin inhibitors (pimecrolimus, tacrolimus) as well as calcipotriol. Sun protection is of the utmost importance. The hypopigmented patches often remain stable for several months or years and may become more apparent during the summer period when the surrounding skin is tanned. The condition usually, but not always, resolves spontaneously after puberty.4–6,10,13
308-nm excimer laser: a hopeful and optional therapy for pityriasis versicolor
Published in Journal of Dermatological Treatment, 2021
Fathia M. Khattab, Farida H. Omran
The differences in the isolation rates in the various studies may be due to the differences in sampling techniques and the use of different media for culture like SDA with olive oil and modified Dixon’s medium. Malassezia furfur can generate an indole alkaloid pityriacitrin which can safeguard M from UV exposure (23). The predominant PV isolate was known as Malassezia globosa. In a later study, from 75% of patients, M. furfur was separated, followed by M. globosa (25%). In the present study, the most common species isolated was Malassezia furfur in 16 patients (61%), followed by M. globosa in 5 patients (19%), M. sympodialis in 4 patients (16%), and M. restricta in 1 (4%). Worldwide studies have reported M. globosa as the predominant isolate in pityriasis versicolor (24).
Seborrheic dermatitis with massive facial hyperkeratosis resembling acquired ichthyosis
Published in Baylor University Medical Center Proceedings, 2020
Brett A. Austin, Alan Vu, William D. Boothe, Cloyce L. Stetson
Although massive hyperkeratosis is unusual for SD, the diagnosis was supported by the symmetric distribution of hyperkeratotic scale on our patient’s face, the presence of budding yeast on the biopsy, and the near complete resolution with oral fluconazole and topical ketoconazole shampoo treatment. In this patient’s case, ketoconazole shampoo was preferable to cream as it is washed off after 5 min, avoiding messy buildup. Clinically there was minimal erythema and no pruritus, as seen in pityriasis versicolor, another Malassezia dermatosis, though our patient lacked truncal involvement. Differential diagnoses of acquired ichthyosis and acrokeratosis paraneoplastica of Bazex were also considered but were not supported by the lack of additional exam findings; in particular, the patient’s acral skin and legs were unremarkable. This presentation highlights the hyperproliferative processes underlying SD’s pathophysiology and may provide insight into Malassezia’s role in the development of SD.
Double-blind randomized placebo-controlled trial to evaluate the efficacy and safety of short-course low-dose oral prednisolone in pityriasis rosea
Published in Journal of Dermatological Treatment, 2018
Sidharth Sonthalia, Akshy Kumar, Vijay Zawar, Adity Priya, Pravesh Yadav, Sakshi Srivastava, Atula Gupta
Pityriasis rosea (PR) is an acute, self-limiting papulo-squamous skin disorder characterized by a distinctive skin rash that has a generally predictable course. The lesions are typically round to oval, erythematous, and have a typical scale with the inner edge free. In three-fourths of the cases, a single, isolated oval scaly pink maculae or patch (the ‘herald’ or ‘mother patch’) appears on the body, particularly on the trunk, upper arms, neck or thighs, although it may be missed by the patient or abate till the patient seeks dermatological consultation. The rash is typically truncal and involvement of extremities is less common, except for in the ‘inverse’ variant. The rash of PR typically lasts ∼5 weeks and resolves by 8 weeks in >80% of patients; although it may last for upto 5 months in adults (1,2). However, the course of PR has been well-documented to sometimes assume persistence as well as relapse or recurrence (3–5). Apart from skin involvement, oral mucosa may also be involved in PR (6,7). Painless oropharyngeal lesions have been reported in 28% patients with PR recently (7). Compared to adults, children show a faster appearance of rash after the herald patch and an overall shorter course of the duration of the eruption (2,8,9). Some epidemiologic features (seasonal variation and clustering in house-holds) suggest that PR may indeed be an infectious disease. Reactivation of latent human herpes viruses (HHV)-6 and 7 infections has been suggested as the most probable etiologic agent (2,10–14).