Illustrated Textbook of Dermatology JS Pasricha, Ramji Gupta
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1Illustrated Textbook of DERMATOLOGY2
3Illustrated Textbook of DERMATOLOGY
Third Edition
J S Pasricha Retd. Professor of Dermatology All India Institute of Medical Sciences New Delhi Ramji Gupta Consultant Dermatologist Escorts Heart Institute New Delhi
4Published by
Jitendar P Vij
Jaypee Brothers Medical Publishers (P) Ltd
EMCA House, 23/23B Ansari Road, Daryaganj
New Delhi 110 002, India
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Illustrated Textbook of Dermatology, 3rd Edition
© 2006, JS Pasricha and Ramji Gupta
All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the authors and the publisher.
First Edition : 1996
Second Edition : 1999
Reprint : 2001, 2003
Third Edition : 2006
Typeset at JPBMP typesetting unit
Printed at Gopsons Papers Ltd., A 14, Sector 60, Noida
5Preface to the Third Edition
Since the publication of the second edition of the Illustrated Textbook of Dermatology, this speciality has made tremendous progress in several areas. Many more diseases have been added to the list of curable diseases, and most of the treatment regimens have been standardised to near perfection. All this progress demands that the old books are revised and new schedules/regimens are incorporated. This book has therefore been rechecked thoroughly to update the new edition with the experiences and developments during this period. The essential character of this book however, that is to cater to the requirements/need of the general practitioners and the undergraduate students has been maintained. A few diseases and photographs have also been added.
We would welcome the comments and criticism of our friends to improve the contents still further.
JS Pasricha
Ramji Gupta
7Preface to the First Edition
With the advances made in the field of dermatology during the last few decades, it has become possible to treat and possibly cure several diseases which till recently were considered to be incurable. This has led to a large number of patients seeking dermatologic advice and this figure is expected to go up in future because a dermatologic patient not only expects his/her disease to be controlled but also to get rid of the marks and scars left behind by the disease process. And over the years, the dermatologists have developed several techniques to achieve these objectives too.
Treating a disease is like fighting a war and if the war has to be won, it is necessary to accurately assess the strength of the adversary. To treat a disease, therefore, an accurate diagnosis and evaluation of the extent and the severity of the disease is very essential.
The dermatologists are in a happy position because the gross pathology is always visible to the clinical dermatologist and he can also make a fair guess of the microanatomy in most of the cases. The lesions are easily available for biopsy and also for topical/intralesional therapy whenever indicated.
The dermatologist has, therefore, to train himself to recognise the signs and symptoms of the various disease processes and visual impressions are very helpful in this regard. We often depend upon a detailed clinical examination and interpretation of the observations (a sort of “Sherlock Holmes” approach) rather than a detailed history as narrated by the patient.
It was with this in mind that we felt the need to bring out the Illustrated Textbook of Dermatology and load it with colour photographs of the various clinical manifestations of dermatologic diseases. We have limited this book to only the common skin diseases and their classical presentations and hope that the undergraduates, general practitioners with interest in dermatology and the family physicians should be able to deal with a large chunk of the dermatology patients, leaving the rarer diseases and atypical presentations of the common diseases for the specialists. An attempt has been made to classify the diseases according to their chief aetiological mechanism, and the old system of classification based on morphological features has been discarded. The treatment methods described in this book are those which are currently employed for the treatment of these diseases.
We pray for wisdom to our colleagues and dermatologic health to our patients.
JS Pasricha
Ramji Gupta
Skin is one of the most important organs of the body because it protects the internal organs from the deleterious environmental influences. No individual can survive if the skin is not intact. The environmental agents which can influence the skin can be categorized into: (1) physical agents such as trauma, friction, extremes of heat and cold, and radiations especially sunlight, (2) chemical agents such as strong acids and alkalis which may burn the skin or lead to irritant dermatitis as with certain chemicals from the plants or incite allergic reactions as with most other chemicals, and (3) biological agents which include a variety of infecting/infesting organisms which can thrive on the skin and produce disease. The skin has several inbuilt mechanisms for interacting with the environmental agents and most of the times the skin is able to protect itself from these agents. The protective ability however, may not always be able to deal with the environmental stimulus and this leads to the production of skin disease. Since the intensity of the environmental agent is likely to vary from time to time and so also the ability of the body to protect itself, a disease is likely to result whenever the protective ability is less than the intensity of the environmental agent. In addition, some individuals may be born with a defective ability to protect themselves, and such individuals succumb to the environmental agent more easily and more frequently than the others. The aetiopathogenesis of skin diseases therefore, is based on an interaction between the nature and the intensity of the environmental agent(s) and the ability of the individual to protect himself from these influences. The protective ability of an individual is influenced by a variety of factors which include; genetic defects, nutritional deficiencies, poor hygiene, over-crowding, co-existence of other diseases and intake of certain drugs.
An interaction between the causative factors and the skin results in specified reaction patterns which lead to the production of characteristic skin lesions and their distribution on the body. In addition, variations in the environmental stimuli from time to time and the natural ability of the body to deal with these factors result in spontaneous remissions and relapses in several of the diseases. Each disease therefore, produces the type of skin lesions which are characteristic for the disease and are distributed in a specific pattern on the body. A close study of the type of the lesions, their location in different regions of the body, and the course that the disease follows with time, thus provide an adequate insight into the causative factors and the pathogenic mechanisms. It is very necessary therefore, to record in detail the circumstances associated with the onset of the disease and the subsequent remissions and relapses if any. In contrast to the other medical specialities, it is also necessary to know a lot more about the habits and the attitudes of the individual patient because the disease may be associated with his occupation, hobbies and pastimes, the diet, the clothes, the cosmetics and the other agents that the person is exposed to during his routine activities. The history-taking in dermatology is thus a special art.
Physical examination of a skin patient is easy because the pathology is visible on the surface and the adjoining normal skin is available for comparison. It is however customary to use specific terms for the different types of skin lesions which a student of dermatology is expected to be familiar with.
The treatment of skin diseases is easier than most other specialities because a large number of the patients can be treated with topical medicines alone.12
It is however important to use the right amount of the medicine in a correct manner for an adequate period to achieve the optimum result. It is necessary that the medicine must reach the site of pathology in an adequate quantity. In case the disease is widespread or a locally applied medicine cannot ordinarily reach the site of pathology, the drug can be administered systemically. It is also possible to use specialised procedures such as occlusive dressings to increase the penetration of the locally applied medicines or inject them intralesionally.
After having cured the skin disease, the patient is likely to be left with residual scars/marks of the original disease and most patients would like even the marks and the scars to be removed. A dermatologist therefore is required to fulfil this responsibility as well. Dermatological surgery is thus an important component of the speciality of dermatology. Surgical procedures can be used to treat such lesions which do not respond to medicinal therapy and also for the residual scars. The various techniques used for this purpose include, chemical cauterization, electrocautery, cryosurgery, lasers or simple surgical procedures. It is important to realise that it is far more easy to treat a dermatologic patient but dermatologic therapy is an art which must be practised to provide perfect treatment to the patients.
Specialised Terms Used in Dermatology
Primary Lesions
A change in the colour of a skin area without any change in the consistency of the skin. A macule may be erythematous, hypopigmented, depigmented, hyperpigmented or any other colour.
A solid indurated raised area of skin less than 5 mm in diameter. It is produced by proliferation of the tissue cells or infiltration with the inflammatory cells.
A papule which is 1–2 mm in size is called a micro-papule, 5–10 mm in size is called a nodule and more than 1 cm is called a tumour.
The surface of a papule/nodule/tumour may be smooth, rough (verrucous), or vegetative.
The shape of a papule may be like an inverted cone (acuminate), elongated like a finger (filiform), hemispherical with a broad base (dome-shaped), spherical wih a narrow base (pedunculated) or a papule may be flat-topped.
A papule situated at the opening of a hair follicle is called a follicular papule.
A raised lesion filled with fluid and less than 5 mm in diameter. A vesicle larger than 5 mm is called a bulla or a blister.
A lesion like a vesicle which contains pus. A pustule may be follicular or non-follicular.
A sudden exudation of fluid in the superficial dermis producing a flat raised area of any size, and often with an orange-peel appearance on the surface. A wheal generally disappears within a few minutes or a few hours but always within 24 hours.
A flake-like lesion which represents visible shedding of the skin.
A flat area of indurated skin which may be raised or depressed below the surface of skin.
It is caused by loss of tissue. This may involve the epidermis, the dermis or both.
A crack in the continuity of the skin surface, usually located in the skin fold.13
A small papule-like lesion containing a keratinous plug. The plug is visible as a black dot at the centre of the lesion in an open comedone (black-head), but not visible in a closed comedone (white-head).
An irregular brownish streak, a few mm long produced by the gravid female acarus penetrating through the stratum corneum.
Thickening of the stratum corneum.
Secondary Changes
Scratching leading to the removal of the top of a lesion or even the skin otherwise.
A diffuse thickening of the skin with hyperpigmentation and severe itching.
A crater-like depression on the top of a papule.
Soddening of the skin associated with scaling or hyperkeratosis.
Loss of the surface layers from a localised area of the skin.
Drying up of the exudate or a necrosed area of the skin.
Proliferation of the cells forming the base of an ulcer.
Healing up of a lesion with fibrosis. An atrophic scar remains below the surface, a hypertrophic scar is raised above the surface, while a keloid grows beyond the limits of the original lesion.
Combination of Lesions
A papule situated at the centre of a macule.
A vesicle situated at the centre of a macule.
Scales present over a macule.
A vesicle located at the top of a papule.
A pustule located at the top of a papule.
A papule covered with scales.
A papule situated over a wheal.
Distribution of the Lesions
Lesions situated along a line.
Lesions tending to form a circle.
When the border of a lesion is more prominent than the central part of the lesion.
When the lesion forms an irregularly shaped area.
When the lesions are situated in a limited area conforming to a neural segment.
When the lesions are situated only on one side of the body and stop short of the mid-line.
When the lesions are situated on both the halves of the body.
When the lesions are an almost mirror image of each other on the two halves of the body.