PGC 5113 2024

PGC 5113 2024. Topic: An overview of other forms of psoriasis Presenter: Yumi.

[Audio] Chronic plaque is the most common form of psoriasis which accounts for more than 90% of psoriasis (1) Guttate psoriasis constitutes 2% of all cases (2) Pustular psoriasis accounts for approximately 1% of all clinical cases (3) Erythroderma is severe, potentially life-threatening, affecting approximately 1-2% of adults with psoriasis (1) (1)Menter A Psoriasis. Second edition. (Menter A, Ryan C, eds.). C-R-C Press, Taylor & Francis Group; 2017. https://www.sciencedirect.com/science/article/pii/S0190962289702875?ref=pdf_download&fr=RR-2&rr=8be72aa328850990 (2) Griffiths C-E-M--, Armstrong AW, Gudjonsson JE, Barker J-N-W-N-. Psoriasis. The Lancet (British edition). 2021;397(10281):1301-1315. doi:10.1016/S0140-6736(20)32549-6 sciencedirect (3) Shah M, Al Aboud DM, Crane JS, and others Pustular Psoriasis. StatPearls. Updated 2023 Aug 8. Access August 29, 2024 nih.

[Audio] The pathophysiology of psoriasis is multifactorial and involves epidermal hyperproliferation, abnormal differentiation of epidermal keratinocytes, and inflammation with immunologic alterations in the skin. For the epidermal hyperproliferation, it is involved by increased D-N-A synthesis and a decreased turnover rate of epidermis. Abnormal keratinocyte differentiation involves increased expression of certain keratins (6 and 16) and a delay in expression of other keratins (1 and 10) that are expressed in normally differentiating skin (7) HLA-Cw6 is a member of the H-L-A class 1 gene family contained in PSORS1 gene on chromosome 6p (1) (2) In the 1970, psoriasis case control studies conducted with classical human leucocyte antigen (H-L-A--) serotyping revealed association with HLA-Cw6 in Finland. It showed the prevalence of HLA-Cw6 was 72.7% in patients with guttate psoriasis and 45.9% with psoriasis compared with 7.4 % in health blood donors. (1) HLA-C locus genotype of 29 caucasian patients with guttate psoriasis showed 100% Cw*0602allele compared with 20% in the control population. (odds ratio = infinity; 95% confidence limits 25.00-infinity; P corrected < 0.0000002). It showed HLA-Cw*0602 playing a part directly in the pathogenesis of guttate psoriasis. (3) Meta analysis of association between HLA-Cw*0602 polymorphism and psoriasis risk was conducted for 3419 psoriasis patients and 3297 health controls. Significant association between HLA-Cw*0602 polymorphism and psoriasis risk in the comparison of positive versus negative alleles (OR = 4.55, 95%CI = 3.65-5.67, P < 0.00001) (5) HLA-Cw6 accounts for up to 50% of psoriasis heritability. In addition, roughly additional loci are thought to be associated with psoriasis. Variation of the genes to these loci that encode the interleukin 23 receptor and in the untranslated region of interleukin 12 B suggest there is a general role of T cells and a specific role of Th17 lymphocytes in psoriasis pathogenesis (8) (1)Menter A Psoriasis. Second edition. (Menter A, Ryan C, eds.). C-R-C Press, Taylor & Francis Group; 2017. (2) Chen L, Tsai TF. HLA-Cw6 and psoriasis. Br J Dermatol. 2018 Apr;178(4):854-862. doi: 10.1111/bjd.16083. Epub 2018 Mar 2. PMID: 29072309. nih (3) Mallon E, Bunce M, Savoie H, Rowe A, Newson R, Gotch F, Bunker CB. HLA-C and guttate psoriasis. Br J Dermatol. 2000 Dec;143(6):1177-82. doi: 10.1046/j.1365-2133.2000.03885.x. PMID: 11122018. nih (5) Wu D, Wu Y, Liu JL, Wang B, Zhang XD. Association between HLA-Cw*0602 polymorphism and psoriasis risk: a meta-analysis. Genet Mol Res. 2011 Dec 15;10(4):3109-20. doi: 10.4238/2011.December.15.2. PMID: 22194166. (7) Price A, Jackson JB, Pathophysiology of Psoriasis. In: Enna SJ, Bylund DB, ed. xPharm: The Comprehensive Pharmacology Reference. 2007. Accessed September 3, 2024. sciencedirect (8) Boehncke WH, Schön MP. Psoriasis. The Lancet (British edition). 2015;386(9997):983-994. doi:10.1016/S0140-6736(14)61909-7 sciencedirect (9) Feldman SR. Psoriasis: Epidemiology, clinical manifestations, and diagnosis. UptoDate. Wolters Kluwer. Updated September 03, 2024. Accessed September 5, 2024 https://www.uptodate.com/contents/psoriasis-epidemiology-clinical-manifestations-and-diagnosis?search=psoriasis&source=search_result&selectedTitle=1%7E150&usage_type=default&display_rank=1#H469480779.

[Audio] Psoriais expression is dependent on gene environemtnal interaction in which it does not manifest unless there is an environemental triggers, such as stress, infection (particularly streptococcal), alcohol consumption, smoking, exposure to drugs, such as lithium, antimarlarials, and N-S-A-I-D and in some cases, sunlight. Weight gain and obesity are both risk factors and triggers (2) For infection, particularly Streptococcal infection is a strong preceding factor for guttate psoriasis. Therefore pharyngitis, tonsillitis, perianal streptococcus and so on could be trigger of guttate psoriasis (1) Approximately two thirds of guttate patients have preceding episode of pharyngitis or tonsillitis (1) (1)Griffiths C-E-M--, Armstrong AW, Gudjonsson JE, Barker J-N-W-N-. Psoriasis. The Lancet (British edition). 2021;397(10281):1301-1315. doi:10.1016/S0140-6736(20)32549-6 (2) Prinz JC. Psoriasis vulgaris--a sterile antibacterial skin reaction mediated by cross-reactive T cells? An immunological view of the pathophysiology of psoriasis. Clin Exp Dermatol. 2001 Jun;26(4):326-32. doi: 10.1046/j.1365-2230.2001.00831.x. PMID: 11422184. nih.

Guttate psoriasis demographic. Occur equally in both genders1 The second most common psoriasis variant in children 1 Most frequently diagnosed in children and young adults under the age of 3017 Older individuals may also be affected17.

Guttate psoriasis common symptoms. Numerous, small scaly papules and plaques6, 25 Usually less than 1cm in diameter ”Guttate” = “drop- like”25 Primarily involve in trunk and proximal extremities6, 25 Approximate 40% evolve into chronic plaque psoriasis9.

[Audio] Extensive tinea corporis may present with numerous annular plaques on the skin. Peripheral scale and central clearing are commonly seen. A potassium hydroxide (K-O-H--) preparation is useful for diagnosis (2) Secondary syphilis is characterized by the development of erythematous to brown macules, papules, or small plaques in a generalized distribution. Involvement of the palms and soles suggests the possibility of this diagnosis. (1) (3) Pityriasis rosea presents with the acute eruption of multiple oval inflammatory plaques. Like guttate psoriasis, the trunk and proximal extremities are prominent sites of involvement. The classic features of a "Christmas tree" pattern distribution and collarette of scale can be useful clues for the identification of pityriasis rosea. At least 50 percent also develop a large, oval plaque (also known as a herald plaque) prior to the development of the widespread eruption (4) W-H-O-. Syphilis. Updated May 21, 2024. Accessed September 4, 2024 who Yee G, Al Aboud AM. Tinea Corporis. StatPearls. Updated August 8, 2023. Accessed September 4, 2024 nih Tudor ME. Al Aboud AM, Leslie SW, Gossman W Syphilis. Updated August 17, 2024. Accessed September 4, 2024 nih Mehlis S, Guttate psoriasis. UptoDate. Wolters Kluwer. Updated November 28, 2022. Accessed September 5, 2024 https://www.uptodate.com/contents/guttate-psoriasis?sectionName=Streptococcal%20infection&search=forms%20of%20psoriasis&topicRef=5664&anchor=H2500010&source=see_link#H2500104.

Erythrodermic psoriasis demographic. One of the rarest forms of psoriasis and can be life threatening Onset is highly variable: 50 patients with erythrodermic psoriasis, average age of onset was 48 years, slight predilection for males in adulthood3.

[Audio] Erythroderma can lead to substantial water loss and electrolyte imbalance, and the high rate of skin cell turnover places a large metabolic demand on the patient. (1) (1) Menter A Psoriasis. Second edition. (Menter A, Ryan C, eds.). C-R-C Press, Taylor & Francis Group; 2017. https://www.sciencedirect.com/science/article/pii/S0190962289702875?ref=pdf_download&fr=RR-2&rr=8be72aa328850990.

Erythrodermic psoriasis differential diagnoses. Diseases Features Atopic dermatitis Early age of onset strong association with allergic rhinitis and asthma, prominent Iinvolvement of flexural surfaces, and disease worsening triggered by xerosis11 Seborrheic dermatitis Dry or greasy flakes of skin, which involve the scalp, eyebrows, glabella, or external ear11.

[Audio] A study of 102 patients in Malaysia reported 2:1 ratio of G-P-P in females versus males (1) 74 G-P-P patients in the U-S reported 1.03:1 ratio of female versus males (2) Over 700 G-P-P patients in Japan 51.5% were female (1) Inpatient database of 1516 people with G-P-P in Japan reported 56% were male (1) In a Malaysians retrospective cohort study from 2010 to 200, 230 patients confirmed G-P-P identified with dermatologist in Malaysian population. The male to female ratio was 1:2.2 and women had a higher prevalence than male (267 vs127). Prevalence age peaks at age 40-59 for women and at age > 60 years for men (2) Zheng M, Jullien D, Eyerich K The Prevalence and Disease Characteristics of Generalized Pustular Psoriasis. American journal of clinical dermatology. 2022;23(Suppl 1):5-12. doi:10.1007/s40257-021-0-0-6-6-4-x nih Choon SE, Wright AK, Griffiths C-E-K--, and others Incidence and prevalence of generalized pustular psoriasis in multiethnic Johor Bahru, Malaysia: a population-based cohort study using routinely captured electronic health records in the Teleprimary Care (TPC®) clinical information system from 2010 to 2020, BJD, 2023; 189(4): 410–418. doi: 10.1093/bjd/ljad158 https://academic.oup.com/bjd/article/189/4/410/7159128?login=false#xd_co_f=NzAwNjJiZTYtYzdkNy00YjlhLTg4OWYtMDc0ZmEyZjAxZTA5~.

Pustular common symptoms. Often appear distressed, often tachypneic, tachycardiac or febrile4 Oropharyngeal mucosa may be hyperemic4 Geographic tongue or fissured tongue may be appreciated4 Well –defined, inflammatory, red, scaling plaques23 Tender to palation23.

[Audio] The European Rare and Severe Psoriasis Expert Network (ERASPEN) supports classification of pustular psoriasis into three phenotype: Generalized pustular psoriasis (G-P-P--), acrodermatitis continua of Hallopeau and palmoplantar pustulosis. (1) Major form of G-P-P includes acute generalized pustular psoriasis (also known as generalized pustular psoriasis of von Zumbusch) and generalized annular pustular psoriasis (also known as subacute GPP). (1) Acute generalized pustular psoriasis is the most classical form and appears as abrupt onset of numerous and widespread painful erythema lesions and systemic symptoms, such as fever, chills.(1)(2) Generalized annular pustular psoriasis is a less acute presentation of G-P-P and developed widespread annular or figurate erythematous plaques studded by pustules.(1) Exanthematic subtype is acute G-P-P pustular eruption without systemic symptoms without systemic symptoms and resolves after few days(1) mpetigo Herpetiformis is acute G-P-P occurs during pregnancy.(1) Localized pustular psoriasis includes acrodermatitis continua and palmoplantar pustulosis.(1) Acrodermatitis continua of Hallopeau (A-C-H--) is pustules affecting the fingers, toes and nail bed (2) Palmoplantar psoriasis is pustules affecting the palms and soles.(2) (1) Kalb RE, Pustular psoriasis: Pathogenesis, clinical manifestations, and diagnosis. UptoDate. Wolters Kluwer. Updated January 24, 2022. Accessed September 5, 2024 https://www.uptodate.com/contents/pustular-psoriasis-pathogenesis-clinical-manifestations-and-diagnosis?search=pustular%20psoriasis&source=search_result&selectedTitle=2%7E38&usage_type=default&display_rank=2#H1451767 (2) Shad M, Al Aboud DM, Crane JS, Kumar S Pustular Psoriasis. StatPearls. Updated April 7, 2023. Accessed April 30, 2024 nih.

[Audio] agep usually classified as a severe cutaneous adverse reaction (S-C-A-R-) to a prescribed drug (a) Over 90% of cases of agep are provoked by medications. Onset of agep is usually within 2 days of exposure to the responsible medication. (a) IL36RN gene mutation is associated with agep which has also been found in G-P-P--. (1)(2) Therefore, it is difficult to distinguish them for patients harboring IL36RN mutation. (1) 54 G-P-P patient s and 64 patients with agep were recruited in United and Japan. G-P-P group had more arthralgia, history of psoriasis of arthritis, family history of psoriasis or arthritis, malaise and psoriasiform plaques of patches and involvement of palms and soles, tenderness and higher recurrence risk. agep patients reported having more presence of causative drug, acute onset from drug administration, history of drug allergy, hemodynamic instability, itch, lower extremity purpura (3) Kalb RE, Pustular psoriasis: Pathogenesis, clinical manifestations, and diagnosis. UptoDate. Wolters Kluwer. Updated January 24, 2022. Accessed September 5, 2024 https://www.uptodate.com/contents/pustular-psoriasis-pathogenesis-clinical-manifestations-and-diagnosis?search=pustular%20psoriasis&source=search_result&selectedTitle=2%7E38&usage_type=default&display_rank=2#H145176 Purvis D Acute generalized exanthematous pustulosis. DermNet. Updated September 2015, Accessed September 5, 2024 dermnetnz Yamanaka-Takaichi M, Watanabe M, Comfere NI, and others Differentiating generalized pustular psoriasis from acute generalized exanthematous pustulosis. Journal of the American Academy of Dermatology. 2024;90(6):1289-1291. doi:10.1016/j.jaad.2024.01.080 jaad(24)00384-0/fulltext.

[Audio] Topical therapy: Topical therapy is indicated for patients with mild to moderate (<10% B-S-A--) and without PsA, topical therapy might be adequate. For sensitive areas, such as face and intertriginous areas, typically require lower potency topical corticosteroids or steroid sparing agents such as topical vitamin D analogues or calcineurin inhibitors to minimized adverse effects. More potent corticosteroid can be used on areas of thicker skin, such as palms, soles, elbows and knees. (1)(2) Topical vitamin D analogues for example calcitriol, calcipotriene, tacalcitol and maxacalcitol are approved for psoriasis, used as monotherapy or in combination with corticosteroids and act through immune modulation and normalization of keratinocyte maturation. These agents are less effective than corticosteroids, their adverse effect profile is favourable (2) Topical retinoids normalize keratinocyte differentiation and supress the immune response but they are irritating. (2) Topical calcineurin inhibitors although nor approved for the treatment of psoriasis are also widely used in managing psoriasis in steroid sensitive areas because of their ability to supress T cell activation and proliferation (1) Phototherapy is indicated for patients with moderate to severe disease, typically characterized by >10% B-S-A and without PsA. Phototherapy is an effective option when topical application to a large area is impractical. Its mechanism involves inducing apoptosis of inflammatory celss, increasing production of anti inflammatory cytokines, T-H-1-7 cell suppression and activation of T-H-2 and Treg cells. Both broadband and narrowband U-V-B are administrated 2-3 times per week. Considerable insurance and co-pay costs, photosensitivity or use of photosensitizing medications are reasons why patients might be reluctant to use phototherapy (1) For patients with moderate to severe psoriasis (>10% BSA), both phototherapy and systemic therapy (oral or injectable) might be prescribed. Systemic therapy is also appropriate even if patients with <10% B-S-A--, especially when face, scalp, palms or soles are affected which can be debilitating or when PsA is also present. (1) Growing understanding of the association of G-P-P with IL36RN mutation. Patients with IL36RN mutations upregulate IL-1 in response to IL-36 stimulation IL-1 antagonist, such as Anakinra and anti IL-36R antibodies were found to be effective for improving G-P-P in preliminary findings (3)(4)(5) Stern RS. Psoriasis. Nature reviews Disease primers. 2016;350(9074):349-16082. doi:10.1038/nrdp.2016.82 (2) Feldman SR, Bhutani T, Chronic plaque psoriasis in adults: Overview of management. UptoDate. Wolters Kluwer. Updated July 8, 2024. Accessed September 4, 2024 https://www.uptodate.com/contents/chronic-plaque-psoriasis-in-adults-overview-of-management?search=psoriasis&source=search_result&selectedTitle=2%7E150&usage_type=default&display_rank=2#H3923589875 (3)Hawkes JE, Duffin KC . Erythrodermic psoriasis in adults. UpToDate. Waltman Kluwer. Updated September 6, 2024. Accessed August 11, 2024. uptodate (4) Guo, J., Zhang, H., Lin, W and others Signaling pathways and targeted therapies for psoriasis. Sig Transduct Target Ther 8, 437:2023,doi:10.1038/s41392-023-0-1-6-5-5-6 nature (5) Mansouri B, Richards L, Menter A Treatment of two patients with generalized pustular psoriasis with the interleukin-1β inhibitor gevokizumab. Br J Dermatol. 2015 Jul;173(1):239-41. doi: 10.1111/bjd.13614. nih.

References. Altman K, Bennett DD, Guttate Psoriasis. Medscape. Updated August 27, 2024. Accessed September 6, 2024. https://emedicine.medscape.com/article/1107850-overview#a1 Boehncke WH, Schön MP. Psoriasis. The Lancet (British edition). 2015;386(9997):983-994. doi:10.1016/S0140-6736(14)61909-7 https://www.sciencedirect.com/science/article/pii/S0140673614619097#cesec120 Boyd AS, Menter A. Erythrodermic psoriasis: precipitating factors, course, and prognosis in 50 patients. Journal of the American Academy of Dermatology. 1989;21(5):985-991. doi:10.1016/S0190-9622(89)70287-5 https://www.sciencedirect.com/science/article/pii/S0190962289702875?ref=pdf_download&fr=RR-2&rr=8be6db5ffc3d07a2 Cockerell CJ. Pustular Psoriasis. Medscape. Updated July 01, 2024. Accessed September 4, 2024. https://emedicine.medscape.com/article/1108220-overview Choon SE, Wright AK, Griffiths CEK, et al. Incidence and prevalence of generalized pustular psoriasis in multiethnic Johor Bahru, Malaysia: a population-based cohort study using routinely captured electronic health records in the Teleprimary Care (TPC®) clinical information system from 2010 to 2020, BJD, 2023; 189(4): 410–418. doi: 10.1093/bjd/ljad158 https://academic.oup.com/bjd/article/189/4/410/7159128?login=false#xd_co_f=NzAwNjJiZTYtYzdkNy00YjlhLTg4OWYtMDc0ZmEyZjAxZTA5~ Feldman SR. Psoriasis: Epidemiology, clinical manifestations, and diagnosis. UptoDate. Wolters Kluwer. Updated September 03, 2024. Accessed September 5, 2024 https://www.uptodate.com/contents/psoriasis-epidemiology-clinical-manifestations-and-diagnosis?search=psoriasis&source=search_result&selectedTitle=1%7E150&usage_type=default&display_rank=1#H469480779 Feldman SR, Bhutani T, Chronic plaque psoriasis in adults: Overview of management. UptoDate. Wolters Kluwer. Updated July 8, 2024. Accessed September 4, 2024 https://www.uptodate.com/contents/chronic-plaque-psoriasis-in-adults-overview-of-management?search=psoriasis&source=search_result&selectedTitle=2%7E150&usage_type=default&display_rank=2#H3923589875 Fujita H, Gooderham M, Romiti R. Diagnosis of Generalized Pustular Psoriasis. American journal of clinical dermatology. 2022;23(Suppl 1):31-38. doi:10.1007/s40257-021-00652-1 Griffiths CEM, Armstrong AW, Gudjonsson JE, Barker JNWN. Psoriasis. The Lancet (British edition). 2021;397(10281):1301-1315. doi:10.1016/S0140-6736(20)32549-6 https://www.sciencedirect.com/science/article/pii/S0140673620325496 Guo, J., Zhang, H., Lin, W. et al. Signaling pathways and targeted therapies for psoriasis. Sig Transduct Target Ther 8, 437:2023,doi:10.1038/s41392-023-01655-6 https://www.nature.com/articles/s41392-023-01655-6.

References. Hawkes JE, Duffin KC . Erythrodermic psoriasis in adults. UpToDate. Waltman Kluwer. Updated September 6, 2024. Accessed August 11, 2024. https://www.uptodate.com/contents/erythrodermic-psoriasis-in-adults#H3557957731 Hill S, Subcorneal pustular dermatosis. DermNet. Accssed September 6, 2024 https://dermnetnz.org/topics/subcorneal-pustular-dermatosis Hoegler KM, John AM, Handler MZ, Schwartz RA. Generalized pustular psoriasis: a review and update on treatment. J Eur Acad Dermatol Venereol. 2018 Oct;32(10):1645-1651. doi: 10.1111/jdv.14949. https://pubmed.ncbi.nlm.nih.gov/29573491/ Kalb RE, Pustular psoriasis: Pathogenesis, clinical manifestations, and diagnosis. UptoDate. Wolters Kluwer. Updated January 24, 2022. Accessed September 5, 2024 https://www.uptodate.com/contents/pustular-psoriasis-pathogenesis-clinical-manifestations-and-diagnosis?search=pustular%20psoriasis&source=search_result&selectedTitle=2%7E38&usage_type=default&display_rank=2#H145176 Kourosh AS. Subcorneal pustular dermatosis. UptoDate. Wolters Kluwer. Updated August 9, 2024. Accessed September 5, 2024 https://www.uptodate.com/contents/subcorneal-pustular-dermatosis?search=Subcorneal%20pustular%20dermatosis%20%28Sneddon-&source=search_result&selectedTitle=1%7E18&usage_type=default&display_rank=1 Mansouri B, Richards L, Menter A. Treatment of two patients with generalized pustular psoriasis with the interleukin-1β inhibitor gevokizumab. Br J Dermatol. 2015 Jul;173(1):239-41. doi: 10.1111/bjd.13614. https://pubmed.ncbi.nlm.nih.gov/25495649/ Mehlis S, Guttate psoriasis. UptoDate. Wolters Kluwer. Updated November 28, 2022. Accessed September 5, 2024 https://www.uptodate.com/contents/guttate-psoriasis?sectionName=Streptococcal%20infection&search=forms%20of%20psoriasis&topicRef=5664&anchor=H2500010&source=see_link#H2500104 Mentor A. Psoriasis. Second edition. (Menter A, Ryan C, eds.). CRC Press, Taylor & Francis Group; 2017. https://www.sciencedirect.com/science/article/pii/S0190962289702875?ref=pdf_download&fr=RR-2&rr=8be72aa328850990 National Psoriasis Foundation. Pustular Psoriasis. Updated December 12, 2022. Accessed September 5, 2024 https://www.psoriasis.org/pustular/ Price A, Jackson JB, Pathophysiology of Psoriasis. In: Enna SJ, Bylund DB, ed. xPharm: The Comprehensive Pharmacology Reference. 2007. Accessed September 3, 2024. https://www.sciencedirect.com/topics/medicine-and-dentistry/pathophysiology-of-psoriasis#chapters-articles.

References. Prinz JC. Psoriasis vulgaris--a sterile antibacterial skin reaction mediated by cross-reactive T cells? An immunological view of the pathophysiology of psoriasis. Clin Exp Dermatol. 2001 Jun;26(4):326-32. doi: 10.1046/j.1365-2230.2001.00831.x. PMID: 11422184. https://pubmed.ncbi.nlm.nih.gov/11422184/ Purvis D. Acute generalized exanthematous pustulosis. DermNet. Updated September 2015, Accessed September 5, 2024 https://dermnetnz.org/topics/acute-generalised-exanthematous-pustulosis Shah M, Al Aboud DM, Crane JS, et al. Pustular Psoriasis. StatPearls. Updated 2023 Aug 8. Access August 29, 2024 https://www.ncbi.nlm.nih.gov/books/NBK537002/ Singh RK, Lee KM, Ucmak D, Brodsky M, Atanelov Z, Farahnik B, Abrouk M, Nakamura M, Zhu TH, Liao W. Erythrodermic psoriasis: pathophysiology and current treatment perspectives. Psoriasis (Auckl). 2016;6:93-104. doi: 10.2147/PTT.S101232. Epub 2016 Jul 20. PMID: 28856115; PMCID: PMC5572467. https://pubmed.ncbi.nlm.nih.gov/28856115/ Stanway A, Guttate psoriasis. DermNet. Updated October 2021. Accessed September 5, 2024 https://dermnetnz.org/topics/guttate-psoriasis Stern RS. Psoriasis. Nature reviews Disease primers. 2016;350(9074):349-16082. doi:10.1038/nrdp.2016.82 Tudor ME. Al Aboud AM, Leslie SW, Gossman W. Syphilis. Updated August 17, 2024. Accessed September 4, 2024 https://www.ncbi.nlm.nih.gov/books/NBK534780/ Union therapeutics. Atopic dermatitis. Accessed September 4, 2024 https://uniontherapeutics.com/atopic-dermatitis/ Universum clinic. Seborrheic dermatitis. Accessed September 4, 2024 https://universum.clinic/en/service/zagalni-napryamki/dermatologiya/seborejnyij-dermatit/ WHO. Syphilis. Updated May 21, 2024. Accessed September 4, 2024 https://www.who.int/news-room/fact-sheets/detail/syphilis Yamanaka-Takaichi M, Watanabe M, Comfere NI, et al. Differentiating generalized pustular psoriasis from acute generalized exanthematous pustulosis. Journal of the American Academy of Dermatology. 2024;90(6):1289-1291. doi:10.1016/j.jaad.2024.01.080 https://www.jaad.org/article/S0190-9622(24)00384-0/fulltext Yee G, Al Aboud AM. Tinea Corporis. StatPearls. Updated August 8, 2023. Accessed September 4, 2024 https://www.ncbi.nlm.nih.gov/books/NBK544360/ Zheng M, Jullien D, Eyerich K. The Prevalence and Disease Characteristics of Generalized Pustular Psoriasis. American journal of clinical dermatology. 2022;23(Suppl 1):5-12. doi:10.1007/s40257-021-00664-x https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8801400/ Litchman G, Nair PA, Syed HA, Le JK, Pityriasis Rosea. StatPearls. Updated March 1, 2024. Accessed September 4, 2024 https://www.ncbi.nlm.nih.gov/books/NBK448091/.