WBR0600

Author	[[PageAuthor::Ayokunle Olubaniyi, M.B,B.S [1] (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::Dermatology
Prompt	[[Prompt::A 47-year-old man presents to the dermatology clinic with a 4 year history of a pruritic lesion on his right hand. The patient explains that the lesion initially started as a small dimple following a bee sting. It then gradually became raised, thickened, and darkened following repeated scratching over the years. Physical examination is remarkable for the lesion shown in the image below. What is this patient's most likely diagnosis? ]]
Answer A	AnswerA::Lichen sclerosus
Answer A Explanation	[[AnswerAExp::Lichen sclerosus is a skin disorder that mainly affects the genitourinary system. The skin often appears thin, whitish, and wrinkled. Common sites include near the clitoris, labia, and in the anal region. It typically manifests with pruritus, dyspareunia, and changes in the appearance of affected skin. The exact etiology is unknown, although it has been postulated to have genetic, autoimmune, and infectious origins.]]
Answer B	AnswerB::Lichen simplex chronicus
Answer B Explanation	[[AnswerBExp::Lichen simplex chronicus (LSC) refers to thickening of the skin secondary to repetitive scratching or rubbing. The hallmark of lichen simplex chronicus is pruritus, which is not only a symptom of the disease, but is also regard as the cause of lichenification.]]
Answer C	AnswerC::Lichen planus
Answer C Explanation	[[AnswerCExp::Lichen planus is a chronic inflammatory disease that affects the skin and the mucous membrane. It is associated with chronic hepatitis C infection. It may affect the skin, oral cavity, genitalia, scalp, nails, or esophagus. The clinical features of cutaneous lichen planus are pruritus, purple, polygonal papules, and plaques (6 Ps) with Wickham striae (white striations). Diagnosis is by biopsy that demonstrates sawtooth lymphocytic infiltration at the dermal-epidermal junction. First line therapy is topical corticosteroids.]]
Answer D	AnswerD::Contact dermatitis
Answer D Explanation	[[AnswerDExp::Contact dermatitis is an chemical-induced inflammation of the skin that directly damage the skin. It is commonly caused by bee sting, nickel, or rubber gloves. Clinical presentation, which is usually preceded by the exposure to the irritant, involves the appearance of pruritic papules and vesicles on an erythematous base. The lesion may become either hyper or hypopigmented with time. Topical corticosteroids are the mainstay of treatment.]]
Answer E	AnswerE::Vitiligo
Answer E Explanation	[[AnswerEExp::Vitiligo is an autoimmune disorder characterized by the presence of auto-antibodies against the melanocyte cells of the skin. It manifests with loss of pigment that results in irregular pale patches of skin. Treatment is with topical corticosteroids and phototherapy using PUVA (Psoralen and ultraviolet A).]]
Right Answer	RightAnswer::B
Explanation	[[Explanation::Lichen simplex chronicus (LSC) refers to thickening of the skin secondary to repetitive scratching or rubbing. The hallmark of lichen simplex chronicus is pruritus, which is not only a symptom of the disease, but is also regard as the cause of lichenification. The lesions of LSC often contain 3 zones (central, middle, and peripheral) with varying degrees of thickening and pigmentation. Common affected areas include the scalp, neck (Lichen nuche), extensor forearms, genitourinary region (giant lichenification of Pautrier), and the extremities. Dermatopathological examination is required to either rule out other diseases that may resemble LSC or primary causes of LSC. Biopsy may demonstrate hyperplasia with hyperkeratosis (thickening of the striatum corneum), parakeratosis (nuclear persistence in the stratum corneum), spongiosis (intercellular edema), and acanthosis (epidermal hyperplasia) along with lengthened rete ridges. First line therapy is topical corticosteroids. Educational Objective: Lichen simplex chronicus (LSC) refers to thickening of the skin secondary to repetitive scratching or rubbing. The hallmark of lichen simplex chronicus is pruritus, which is not only a symptom of the disease, but is also regard as the cause of lichenification. References: Lynch, Peter J. Lichen simplex chronicus (atopic/neurodermatitis) of the anogenital region. Dermatologic therapy.2004;17(1):8-19. Gantcheva ML. Lichen simplex chronicus in ed. Katsambas AD and Lotti TM, European Handbook of Dermatological Treatments. Springer Berlin Heidelberg, 2003. Image attribution: Lichen simplex chronicus 3.jpg by user:kilbad on wikipedia.org licensed under the Creative Commons Attribution 3.0 License. ]]
Approved	Approved::No
Keyword	WBRKeyword::Lichen simplex chronicus, WBRKeyword::Pruritus, WBRKeyword::Bee sting, WBRKeyword::Itching, WBRKeyword::Rubbing, WBRKeyword::Lichenification, WBRKeyword::Lichen planus, WBRKeyword::Contact dermatitis, WBRKeyword::Lichen sclerosus, WBRKeyword::Vitiligo
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