Parasitic Skin Infections

Parasitic Skin Infections Indian Medical PG Question 1: Which physical finding is most useful in diagnosing scabies in genital lesions?

• A. Vesicular lesions on shaft of penis
• B. Burrows in genital area (Correct Answer)
• C. Pustules on glans penis
• D. Excoriated nodules on scrotum

Parasitic Skin Infections Explanation: ***Burrows in genital area*** - The presence of **burrows** is the **pathognomonic sign of scabies**, representing the tunnels dug by the female mite. - While scabies can cause varied lesions, identifying these **serpiginous, thread-like burrows** is the most diagnostic physical finding. *Vesicular lesions on shaft of penis* - **Vesicular lesions** can be seen in various conditions like **herpes simplex virus (HSV)** infection, making them less specific for scabies. - While scabies can sometimes present with vesicles, they are not the primary diagnostic feature. *Pustules on glans penis* - **Pustules on the glans penis** are more indicative of conditions like **bacterial folliculitis** or other sexually transmitted infections (STIs), such as **gonorrhea**. - Scabies typically does not present with pustules as its primary lesion. *Excoriated nodules on scrotum* - While **scabietic nodules**, particularly on the scrotum, are a recognized manifestation of scabies, especially in chronic cases, they are often **excoriated due to intense itching**. - These nodules are a common sign but are not as specific as finding a burrow, which directly demonstrates the mite's activity.

Parasitic Skin Infections Indian Medical PG Question 2: A 42-year-old Bengali male presents with painless nodules over the face. The face is erythematous, and the surface of some of the large nodules is discolored. He gives a history of an insect bite in the past while he went to the jungle for work. What is the most likely diagnosis?

• A. Chronic Fungal infections
• B. Cutaneous Leishmaniasis (Correct Answer)
• C. Cutaneous tuberculosis
• D. Leprosy

Parasitic Skin Infections Explanation: ***Cutaneous Leishmaniasis*** - The presentation of **painless erythematous nodules** on the face, especially in a person with a history of **insect bites** and exposure to a **jungle environment** (where sandflies, vectors of Leishmania, are common), strongly suggests cutaneous leishmaniasis. - The discoloration of the surface of large nodules is also consistent with the typical appearance of **chronic cutaneous leishmaniasis lesions**. *Chronic Fungal infections* - While chronic fungal infections can cause skin nodules, they typically present with features like **scaling, itching, or satellite lesions**, which are not described here. - The specific history of **insect bites** and geographical context points away from common fungal etiologies. *Cutaneous tuberculosis* - Cutaneous tuberculosis can manifest as nodules (**lupus vulgaris** or **scrofuloderma**), but these are often associated with other signs of tuberculosis, such as **pulmonary involvement** or **lymph nodal enlargement**, and typically have a slower progression. - The history of **insect bite** is not a primary risk factor for cutaneous tuberculosis. *Leprosy* - Leprosy, particularly **lepromatous leprosy**, can cause extensive facial nodules, but these are often associated with **nerve involvement** leading to sensory loss, and the lesions tend to be diffusely infiltrative rather than discrete, discolored nodules. - The rapid onset or history of a single insect bite is less characteristic of leprosy, which has a very **long incubation period**.

Parasitic Skin Infections Indian Medical PG Question 3: Mass Drug Administration is NOT routinely used as the primary strategy for:

• A. Vitamin A Deficiency
• B. Scabies (Correct Answer)
• C. Lymphatic Filariasis
• D. Worm infestation

Parasitic Skin Infections Explanation: ***Scabies*** - While **mass drug administration with oral ivermectin** has shown effectiveness in specific endemic outbreak settings, MDA is generally **not the primary recommended strategy** for routine scabies control in most public health contexts. - Scabies control typically prioritizes **case finding, contact tracing, simultaneous household treatment, and environmental decontamination**—which are more complex to implement than standard MDA programs. - Unlike the other conditions listed, scabies lacks well-established **routine MDA programs** at the scale of national public health initiatives, making it the least suitable option for MDA among these choices. *Vitamin A Deficiency* - **Vitamin A supplementation** through MDA is a **highly effective and widely implemented** WHO-recommended strategy to combat Vitamin A deficiency in at-risk populations, particularly children under 5 years. - Regular mass supplementation helps prevent **xerophthalmia** and reduces morbidity and mortality from infectious diseases. - This is a cornerstone of routine public health programs globally. *Lymphatic Filariasis* - **Lymphatic filariasis** is a classic example where MDA with anti-filarial drugs like **diethylcarbamazine (DEC), albendazole,** or **ivermectin** is the cornerstone strategy for interrupting transmission. - MDA is the **primary WHO-recommended approach** to achieve elimination of lymphatic filariasis, with established national programs in endemic countries. *Worm infestation* - **Mass deworming programs** using drugs like **albendazole** or **mebendazole** represent highly effective and well-established forms of MDA for controlling **soil-transmitted helminth infections**. - These routine programs significantly reduce disease burden in school-aged children, improving nutritional status, growth, and learning outcomes.

Parasitic Skin Infections Indian Medical PG Question 4: Transmission assessment survey is for?

• A. Plasmodium falciparum
• B. Plasmodium vivax
• C. Leishmania donovani
• D. Wuchereria bancrofti (Correct Answer)

Parasitic Skin Infections Explanation: ***Wuchereria bancrofti*** - The **Transmission Assessment Survey (TAS)** is explicitly designed by the World Health Organization (WHO) to determine if **lymphatic filariasis (LF)**, primarily caused by *Wuchereria bancrofti*, has been successfully eliminated as a public health problem. - It uses specific thresholds of **microfilaria prevalence** in endemic areas to decide when mass drug administration (MDA) can be stopped. *Plasmodium falciparum* - This parasite causes **falciparum malaria**, and its transmission is assessed through methods like **malaria indicator surveys (MIS)**, entomological surveys, and case detection rates, not TAS. - The goal for *Plasmodium falciparum* is **malaria control** and elimination, but it doesn't utilize the TAS methodology. *Plasmodium vivax* - This parasite causes **vivax malaria**, similarly assessed by malaria-specific surveys and surveillance, including **passive and active case detection**, not a TAS for lymphatic filariasis. - While efforts are made for *Plasmodium vivax* elimination, it requires different diagnostic and surveillance strategies due to its hypnozoite stage. *Leishmania donovani* - This parasite is responsible for **visceral leishmaniasis (kala-azar)**, and its transmission is monitored through surveillance of human cases, vector control assessment, and serological surveys. - The elimination program for **kala-azar** in endemic areas uses **different indicators and survey methods** than the TAS for lymphatic filariasis.

Parasitic Skin Infections Indian Medical PG Question 5: A child presented with perianal itching. The swab specimen is shown in the image. What is the diagnosis?

• A. Enterobius (Correct Answer)
• B. Ascaris
• C. Trichiura
• D. Ancylostoma

Parasitic Skin Infections Explanation: ***Enterobius*** - The image shows **D-shaped** (plano-convex) and **transparent eggs**, which are characteristic of *Enterobius vermicularis* (**pinworm** or **threadworm**). - **Perianal itching**, especially at night, is the hallmark symptom due to the female worm migrating to the perianal region to lay eggs. *Ascaris* - *Ascaris lumbricoides* eggs are typically **round to oval**, with a thick, mamillated (bumpy) outer shell, or smooth in the case of decorticated eggs, which is different from the eggs pictured. - Infection with *Ascaris* can cause pulmonary symptoms (Loeffler's syndrome) and intestinal obstruction, but not typically perianal itching. *Trichiura* - *Trichuris trichiura* (**whipworm**) eggs are distinctly **barrel-shaped** with prominent **polar plugs** at each end, which is not seen in the image. - Whipworm infection is often associated with bloody diarrhea, rectal prolapse, and growth retardation, not primarily perianal itching. *Ancylostoma* - *Ancylostoma duodenale* and *Necator americanus* (hookworms) eggs are typically **oval** with a **thin shell** and segmented embryo (morula stage) within, which lacks the distinct D-shape and transparency of the pictured eggs. - Hookworm infection primarily causes iron-deficiency anemia and can lead to cutaneous larva migrans, not perianal itching as a primary symptom.

Parasitic Skin Infections Flashcard 1 of 5

Question: Crusted scabies (_____ or hyperkeratotic scabies) is found in immunocompromised or debilitated patients

Answer: Norwegian (country)

Parasitic Skin Infections Flashcard 2 of 5

Question: Pediculosis _____ (also known as "Pediculosis vestimenti" and "Vagabond's disease") is a cutaneous condition caused by body lice

Answer: corporis

Parasitic Skin Infections Flashcard 3 of 5

Question: _____ is the most common symptom associated with scabies

Answer: Nocturnal pruritis

Parasitic Skin Infections Flashcard 4 of 5

Question: The burrows are in scabies are mainly seen in stratum _____

Answer: corneum

Parasitic Skin Infections Flashcard 5 of 5

Question: In cutaneous larva migrans, the larval track progresses at approximately _____ cm/hr

Answer: 1