A CHRONIC COUGH
History
Donna is a 12-year-old girl seen in the GP surgery with her mother. This is her fourth visit in 3 months. Her initial presentation was with a headache, fever, malaise, a sore throat and a symmetrical non-pruritic rash on her arms and hands. The lesions varied in size and character, some being simple red macules and others being up to 2 cm in diameter with a central, slightly dusky centre and a surrounding ‘halo’ of varying erythema. A diagnosis of a viral infection was made. However, these symptoms progressed to include a cough productive of white sputum. The computer records show that the emergency GP they consulted at the time heard some crackles throughout the chest and prescribed a course of clarithromycin. All of her symptoms have resolved, except for her cough. This is mostly during the day and is not waking her or her family. However, it is disrupting her life because she is being sent home from school and her parents have excluded her from sport. It is a spasmodic unproductive cough that comes in bouts, which are occasionally severe enough to cause vomiting. Another GP gave her a trial of inhaled salbutamol but with no apparent improvement. She has never had any obvious nasal symptoms. Donna is otherwise well and recently started her periods. She is fully immunized. Her father has a history of asthma. Her mother smokes but ‘not around the children’. There is no history of recent foreign travel and no family history or contact with tuberculosis.
Examination
Donna looks well. Her height is on the 91st centile and her weight is on the 75th centile. There has been appropriate weight gain since her illness began. She is not clubbed or anaemic. She is afebrile. There is no significant lymphadenopathy. Examination of the ears, nose and throat is normal. Her pulse is 72 beats/min, her heart sounds are normal and there are no murmurs. Inspection of the chest is normal and her respiratory rate is 18 breaths/min. Expansion, percussion and auscultation are normal. Examination of the abdomen is unremarkable.
INVESTIGATIONS
Full blood count Normal
C-reactive protein Normal
Erythrocyte sedimentation rate Normal
Chest X-ray 6 weeks previously Normal
Questions
• What is the differential diagnosis?
• What is the most likely diagnosis?
• What was the rash?
• What is the management?
Medicine
Cough is one of the commonest symptoms in childhood and indicates irritation of nerve receptors within the airway.
Differential diagnosis of a recurrent or persistent cough in childhood
• Recurrent viral URTIs – very common in all age groups but more so in infants and toddlers
• Asthma – unlikely without wheeze or dyspnoea • Allergic rhinitis – often nocturnal due to ‘post-nasal drip’
• Chronic non-specific cough – probably post-viral with increased cough receptor sensitivity
• Post-infectious – a ‘pertussis (whooping cough)-like’ illness can continue for months following pertussis, adenovirus, mycoplasma and chlamydia
• Recurrent aspiration – gastro-oesophageal reflux
• Environmental – especially smoking, active or passive
• Suppurative lung disease – cystic fibrosis or primary ciliary dyskinesia
• Tuberculosis
• Habit
Donna is otherwise healthy with no evidence of any chronic disease and she has a normal chest X-ray. Although her father has asthma, she has no convincing features of atopy and she did not respond to inhaled salbutamol. The history is not that of recurrent aspiration. The abrupt onset of symptoms with systemic features suggests infection, and the description of her cough as spasmodic bouts with occasional vomiting is that of a ‘pertussis-like’ illness. This can continue for months following an infection, as can a chronic, non-specific cough following a viral infection. The acute history is very typical, although not specific, for Mycoplasma pneumoniae infection. This aetiology is supported by the rash, which has the characteristic clinical features of erythema multiforme (EM). As expected from the name, EM has numerous morphological features but the diagnosis is made on finding the classic target-like papules with an erythematous outer border, an inner pale ring and a dusky purple to necrotic centre. It is occasionally mistaken for urticaria, but EM is largely asymptomatic and the lesions do not fade within 24 hours. Infection, frequently mycoplasma, is one of numerous causes. No treatment is indicated. These symptoms cause understandable distress and anxiety and a belief that there must be something wrong and that treatment is necessary. As in this case, children must have a thorough clinical evaluation to exclude serious and treatable pathology. This, plus an explanation that they can expect the cough to take months to resolve, is usually adequate to reassure families. Explore the reasons behind their anxiety and encourage a return to normality knowing that no harm is being done. A watch-and-wait policy is best, resisting any pressure to investigate further or to try other treatments such as inhaled steroids. The one thing the family can do is to ban smoking in the house and this could be the spur for her mother to give up altogether.
KEY POINTS
• Cough is one of the commonest symptoms in childhood and is usually due to viral respiratory tract infections.
• A chronic cough may indicate a serious disorder and all such children should have a thorough clinical review to exclude significant pathology.
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