The following are the question related to dermatology asked in AIIMS May 2006 with detailed and referenced answers

 

Solved by Dr. Premanshu Bhushan

MD (Dermatology)

Homepage::http://drpremanshu.googlepages.com/

Blog page: http://drpremanshu.blogspot.com/

 

31. Anagen phase of the hair indicates:

1. The phase of activity and growth.

2. The phase of transition.

3. The phase of resting.

4. The phase of degeneration.

 

ANSWER: 1. The phase of activity and growth.

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 17: answer of Q 20. Module 1. 

 

Explanation: Hair grows at different rates in different regions of the body. On the human scalp, the daily growth rate is around 0.3 mm. In women, scalp and body hair grows faster and slower, respectively, than in men. The activity of hair follicles is intermittent.Anagen is the active period, which may last for 3 or more years. Telogen is the resting phase, usually lasting about 3 months. Catagen is the transition or regression phase, usually approximately 3 weeks in duration. In the human scalp, at any one point in time, approximately 84% of hair is in anagen, 14% in telogen, and 2% in catagen. Assuming that the scalp contains about 100,000 hairs, it can reasonably be expected that 100 hairs will be shed daily. Histologically, the hair follicle consists of three parts: the lower portion, which extends from the base of the follicle to the insertion of the arrector pili muscle; the isthmus, which extends from the insertion of the arrector pili muscle to the entrance of the sebaceous duct; and the infundibulum, which extends from the entrance of the sebaceous duct to the follicular orifice.


32. ‘Chancre redux’ is a clinical feature of:

1. Early relapsing syphilis.

2. Late syphilis.

3. Chancroid.

4. Recurrent herpes simplex infection.

 

ANSWER: 1. Early relapsing syphilis.

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 168; Module 7.

 

Explanation: Latent syphilis is a state when there are no symptom or signs of syphilis; only positive serological tests & normal CSF. The first two years are called Early Latent syphilis and there may be relapses (Early relapsing syphilis) ---mainly of the secondary but at times of primary type (Chancre Redux: Appearance of relapsing lesions at the site of healed chancre)—and the disease remains quite infective and infectivity decreases rapidly after 2 years. Late Latent syphilis is latency after 2 years.

 

33. Max Joseph’s space is a histopathological feature of:

1. Psoriasis vulgaris.

2. Lichen planus.

3. Pityriasis rosea.

4. Parapsoriasis.

 

ANSWER: 2. Lichen planus.

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 62 & 65 (Q 14) and p 51;Module 3.

Explanation: The histological features of lichen planus include hyperkeratosis, irregular acanthosis (saw toothing), focal wedge shaped hypergranulosis, Civatte or colloid bodies (Apoptotic), basal cell degeneration (BCD), band-like infiltrate of lymphocytes at the DEJ.  Immunofluorescence reveals IgM staining of colloid bodies (Bunch of grapes) and shaggy deposition of fibrin at DEJ. In bullous and vesicular lichen planus, the clefts, by confluence, produce detachment of the damaged epidermis. The potential cleft, or the space through which cleavage occurs has been referred to as the “Max-Joseph”space.

 

34. Ivermectin is indicated in the treatment of:

1. Syphilis.

2. Scabies.

3. Tuberculosis.

4. Dermatophytosis.

 

ANSWER: 2. Scabies.

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 31; Module 2.

 

Explanation: Ivermectin is effective as an oral drug for Scabies. It is given as a single stat dose of 200 micrograms/kg body weight. It is also used successfully in heavy infestations as seen in immunocompromized patients (Norwegian scabies). The mechanism of action of Ivermectin is by inhibition of glutamate-gated chloride ion channels & other ligand-gated chloride channels, such as those gated by the neurotransmitter gamma-aminobutyric acid (GABA) present in invertebrate nerve and muscle cells. This binding leads to an increase in the permeability of the cell membrane to chloride ions with hyper-polarization of the nerve or muscle cell, resulting in paralysis and death of the parasite.

 

35. The main cytokine, involved in erythema nodosum

leprosum (ENL) reaction is:

1. Interleukin-2.

2. Interferon - gamma.

3. Tumor necrosis factor - alpha.

4. Macrophage colony stimulating factor.

 

ANSWER: 3. Tumor Necrosis Factor-alpha (TNF-α)

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 186 & 198(Q 45); Module 7 ; Leprosy , Hastings RC, Opromolla DVA, Second edition, p 231.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

 

Explanation: NOTE: This is a tough one as it is an investigational issue and should not really concern the postgraduate entrance aspirants. However, since it has been asked here is brief summary.  Those interested may also see:   Tadesse A, Shannon EJ. Effects of thalidomide on intracellular Mycobacterium leprae in normal and activated macrophages. Clin Diagn Lab Immunol. 2005 Jan;12(1):130-4. Freely available at Pubmed central:

  http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=15642997

 

Type II lepra reaction is also known as erythema nodosum leprosum (ENL). The sequence of events which precipitate ENL as well as the exact mechanism have not yet been clearly delineated. It has been suggested that release of Mycobacterium leprae antigens from macrophages may be a factor which initiates ENL. The released antigen may then complex with antibodies, initiating complement fixation and production of inflammatory cytokines like tumor necrosis factor alpha (TNF-α).

ENL is a type 3 hypersensitivity (Arthus phenomenon) reaction mediated by humoral immunity. It is a TH2 type response leading to humoral response and an Immune complex mediated reaction. This TH2 type response leads to a predominance of TNF-α and Interleukin 4, 5, 6 and 10. On the other hand, IL-1, 2 and interferon gamma are seen in TH1 response with cell mediated reaction as seen in type I lepra reaction.  Clinically ENL presents as crops of red, tender subcutaneous nodules over face, extremities as well as trunk in BL and LL patients, usually after 6 months of treatment. The nodules heal within 3-5 days with bruise like pigmentary changes. The eruption is associated with fever, malaise, anorexia and in more severe cases with neuritis, periosteitis, iritis, glomerulonephritis, orchitis etc.

Thalidomide and pentoxifylline both inhibit the TNF-α and hence may be effective in management of ENL.

 

36. The following drug is not used for the treatment of type II lepra reaction:

1. Chloroquin.

2. Thalidomide.

3. Cyclosporine.

4. Corticosteroids.

 

ANSWER: NOTE: Possibly a WRONG QUESTION: best possible choice : none of the above. Second best possibility is 3. Cyclosporine. (take your pick !!!)

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 186 & 198(Q 45); Module 7; Hastings’ Leprosyand van Gompel A, van den Enden E, van den Ende J Cyclosporine A is not very effective in erythema nodosum leprosum (ENL). Trop Geogr Med. 1994;46(5):331.

 

Explanation:  The question is probably wrong and should have been “The following drug is not used for the treatment of type I lepra reaction”. In that case the answer should have been Thalidomide, as it has no role in type-I reactions in leprosy.

However, considering that the question is correct, we are asked to choose the drug which can not be used in type-II lepra reaction. Truly speaking all mentioned drugs have been used in type-II lepra reaction. The treatment of choice is Thalidomide and systemic steroids remain second best drug. Other drugs used are chloroquine, aspirin, antimonials and immunosuppressants like cyclophosphamide, azathioprine etc. Recently, pentoxifylline has been found to be effective.

As far as Cyclosporine is concerned it definitely has a role in type-I lepra reaction. However, in type-II lepra reaction cyclosporine has a limited role and patho-physiologically type-II reaction is an Immune complex mediated (Type 3) response brought about by the B cells while cyclosporine is more effective against the T cells. Hence, while cyclosporine can be used in type I lepra reaction (cell mediated or type 4 reaction); it has a minimal role in type-II lepra reaction. Therefore no clear cut answer is possible for this question; but I would suggest either leave the question or mark Cyclosporine as the correct choice. Remember however, that if it indeed is a wrong question with a typographical error; then the answer would be Thalidomide.

 

 

37. The following test is not used for diagnosis of leprosy:

1. Lepromin test.

2. Slit skin smear.

3. Fine needle aspiration cytology.

4. Skin biopsy.

 

ANSWER: 1. Lepromin test.

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 187-88; Module 7.

Explanation: Lepromin testing is not a diagnostic procedure as it is only an indication of host immunity. It is mediated by CMI and it is positive in TT and BT and negative in all other forms of leprosy. It is an important component of Ridley Jopling classification. It is a CMI mediated type IV hypersensitivity reaction to M. leprae antigens. The two main types of lepromin are the integral Mitsuda-type and Dharmendra’s lepromin. Mitsuda lepromin gives an early reaction of Fernandez (similar to tuberculin) at 48-72 hours and late Mitsuda reaction at 3-4 weeks presenting as a skin lesion similar to TT/ BT leprosy. Dharmendra lepromin has soluble antigens only (no lipids) and gives only early reaction. Slit smears can be used to detect the AFB in tissue as can the FNAC. Skin biopsy helps us to arrive at a diagnosis of the type of leprosy (TT, BT, BB, BL or LL) and can also be used to calculate the bacillary load of AFB in tissue.

 

38. Air-borne contact dermatitis can be diagnosed by:

1. Skin biopsy.                

2. Patch test.

3. Prick test.

4. Estimation of serum IgE levels.

 

ANSWER:2. Patch test.

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition,  p 83; Module 4.

 

Explanation: Air-borne contact dermatitis (ABCD) is a type of allergic contact dermatitis (ACD). ACD is confirmed with a patch testing as it detects a type-IV hypersensitivity reaction to exogenous allergens. Parthenium hysterophorous (congress grass) is the commonest allergen causing ABCD in India. Skin biopsy will only identify a dermatitis but there are no specific changes to any dermatitis and it is the clinical scenario that will lead to a diagnosis. Prick-test is to identify immediate type hypersensitivity (type-I), while serum IgE is a marker of a hypersensitive state seen in atopic dermatitis, asthma, parasitic infestations and hypereosiniophilia syndromes.

 

19. Which of the following statements about lepromin test is not true?

1. It is negative in most children in first 6 months of life.

2. It is a diagnostic test.

3. It is an important aid to classify type of leprosy disease.

4. BCG vaccination may convert lepra reaction from negative to positive.

 

ANSWER: 2. It is a diagnostic test.

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 187-88; Module 7.

Explanation: Please see the explanation of Question no. 37. Lepromin testing is not a diagnostic procedure as it is only an indication of host immunity.

With regards to other choices, since most of children have a relatively week immune system (CMI) in the first 6 months of life the Lepromin test is usually negative. It is a part definition in the Ridely Jopling classification scheme and is positive in TT and BT but is negative in BB, BL and LL; because the CMI to M. leprae goes down in these types of leprosy. There is a partial yet significant cross-reactivity between the antigens of M. tuberculosis and M. leprae as well as BCG (all are mycobacteria !!) Therefore BCG vaccination may convert the lepromin negative patient to lepromin positive nad this feature has been used to develop possible vaccines for leprosy (not very successful though!).

 

168. A 48 year old sports photographer has noticed a small nodule over the upper lip from four months. The nodule is pearly white with central necrosis, telangiectasia. The most likely diagnosis would be

1. Basal cell carcinoma.

2. Squamous cell carcinoma.

3. Atypical melanoma.

4. Kaposis sarcoma.

 

ANSWER: 1. Basal Cell Carcinoma

 

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 152; Module 6.

 

Explanation :  This is a typical description of basal cell carcinoma. Basal cell carcinoma is the commonest human cancer (together with other non melanoma skin cancers i.e. NMSC) found mostly on sun-exposed areas in fair-skinned individuals. They appear as “translucent” or "pearly” papule with associated telangiectasis which crosses over the shiny papule. When they ulcerate in the center; their margins retain pearly and translucent character (rolled up).

 

178. A 35 year old premenopausal patient has recently developed a 1.5 cm sized pigmented lesion on her back. Which of the following forms of tissue diagnosis will you recommend for her?

1. Needle biopsy.

2. Trucut biopsy.

3. Excision biopsy.

4. Incisional biopsy.

 

ANSWER: 3. Excision biopsy.

Reference : Dermatology in a Week, Premanshu Bhushan, First edition, p 153; Module 6.

Explanation : The appearance of a new pigmented lesion on the skin is a danger signal of malignant melanoma. As a general rule no pigmented lesion should undergo an incisional biopsy lest there be spread of a possible melanoma.  Similarly, a needle or trucut biopsy will also have the risk of spread of the melanoma cells. By the same philosophy they should be excised with adequate margins and sent for histological examination to rule out melanoma.