Period of infectivity -From onset of prodromal period to 4 days after appearance of rash. Clinical features - Illness of infection -Febrile catarrhal

days. Period of infectivity -From onset of prodromal period to 4 days after appearance of rash. Clinical features - Illness of infection -Febrile catarrhal attack with fleeting rash in a few hours after exposure to measles. 1. Prodromal stage -usually 4-5 days. (a) Fever - Abrupt rise of temperature to about 40°C (102°F). (b) Catarrh - Coryza, conjunctivitis, photophobia and hacking cough. (c) Koplik's spots (Enanthema) pathognomonic. Appear on 2nd day as minute pin-point bluish white specks with slight reddish mottled areola around them, on buccal mucosa usually opposite lower molars. They look like grains of salt. Variable in number. Occasionally large spots few in number. The spots begin to fade with appearance of rash. Red blotches may be seen on soft palate. Koplik's spots may sometimes occur in the lower lip in front of the lower incisors, and in severe cases the palate and rest of the mucosa are peppered with these spots. (d) Laryngeal involvement -Hoarseness and laryngeal stridor. (e) Gl - Persistent vomiting and diarrhoea. (f) Fleeting rashes - either urticarial or erythematous. 2. Exanthematous stage - (a) Rash - On 5th day, red macules appear first behind ear, along hair line and on posterior parts of cheeks and spread rapidly in a few hours all over the body. Macules appear in crops which by confluence form blotches with crescenteric or thumb nail edge Fully erupted rash deepens in colour, petechiae may occur. In severe measles the rash is confluent, the face is swollen and disfigured and together with the photophobic eyes creates the typical measly appearance. (b) Mucous membrane involvement - includes conjunctivitis, rhinitis, stomatitis, laryngitis, tracheitis and bronchitis. There may also be gastroenteritis. 3. STAGE OF DEFERVESCENCE -Temperature falls by crisis or rapid lysis in 24 to 48 hours. Rash fades from face downwards in same sequence as its appearance, and leaves brown staining often followed by branny desquamation. The more severe the measles, greater the extent of desquamation. At times the normal rash of measles instead of fading becomes a deep purple (purpuric measles) and this may persist for a week or two. Varieties - 1 Modified measles - In measles modified by gamma globulin all symptoms and signs may be suppressed except the rash in the form of discrete macules scattered over the trunk. 2 Measles in adults -Constitutional symptoms may be more severe but less tendency to complications. 3. Atypical measles - in children who have received measles vaccine. Fever with petechial rash and oedema on lower legs and dorsum of feet. 4. Morbilli bullosi - Severe variety in which some of the lesions become bullous. May occur in malnourished children. 5. Hemorrhagic measles (black measles) - Hemorrhages into skin and bleeding from any or all of the body orifices. Complications - 1. Secondary bacterial otitis media. 2. Pneumonia or bronchopneumonia - main cause of death. During the latter part of exanthematous stage, combination of measles and adenovirus infection produces most severe symptoms and prolonged course. 3. Laryngotracheobronchtitis (croup) - due to measles virus. May give rise to stridor. 4. Herpes simplex gingivostomatitis - Vesicles in mouth which rapidly ulcerate causing fever, salivation and difficulty in feeds Disseminated herpes is rare. 5. Acute post-infective encephalitis - is the most common neurological