Breath-holding in water should always be supervised by a second person, as by hyperventilating, one increases the risk of shallow water blackout because insufficient carbon dioxide levels in the blood fail to trigger the breathing reflex.A continued lack of oxygen in the brain, hypoxia, will quickly render a person unconscious, usually around a blood partial pressure of oxygen of 25–30 mmHg. An unconscious person rescued with an airway still sealed from laryngospasm stands a good chance of a full recovery. Artificial respiration is also much more effective without water in the lungs. At this point, the person stands a good chance of recovery if attended to within minutes. More than 10% of drownings may involve laryngospasm, but the evidence suggests that it is not usually effective at preventing water from entering the trachea. The lack of water found in the lungs during autopsy does not necessarily mean there was no water at the time of drowning, as small amounts of freshwater are readily absorbed into the bloodstream. Hypercapnia and hypoxia both contribute to laryngeal relaxation, after which the airway is effectively open through the trachea. There is also bronchospasm and mucous production in the bronchi associated with laryngospasm, and these may prevent water entry at terminal relaxation.The hypoxemia and acidosis caused by asphyxia in drowning affect various organs. There can be central nervous system damage, cardiac arrhythmia, pulmonary injury, reperfusion injury, and multiple-organ secondary injury with prolonged tissue hypoxia.A lack of oxygen or chemical changes in the lungs may cause the heart to stop beating.
This is because children from countries of high incidence of tuberculosis can contract the lesion after contact with tuberculous sputum, by walking barefoot, sitting or playing on the ground.When recent, the skin lesion has the outside appearance of a wart or verruca, thus it can be confused with other kinds of warts. It evolves to an annular red-brown plaque with time, with central healing and gradual expansion in the periphery. In this phase, it can be confused with fungal infections such as blastomycosis and chromoblastomycosis. Cause
Diagnosis
The diagnosis is confirmed by a skin biopsy and a positive culture for acid-fast bacilli. A PPD test may also result positive. Treatment
Therapy for cutaneous tuberculosis is the same as for systemic tuberculosis, and usually consists of a 4-drug regimen, i.e., isoniazid, rifampin, pyrazinamide, and ethambutol or streptomycin. See also
Tuberculosis
Tuberculosis classification
Tuberculosis diagnosis
Tuberculosis treatment
Prosectors paronychia

Notes
References
Goldman, G.;  Bolognia, J.L. Pinpointing cutaneous signs of tuberculosis: is it a common wart, or tuberculosis verrucosa cutis? Journal of Critical Illness,  Dec. 2002. External links
 Media related to Tuberculosis verrucosa cutis at Wikimedia Commons
Cutaneous tuberculosis. eMedicine.