The skin on the face around the nose and mouth is usually affected first. The initially itchy and reddened areas develop pustules, possibly also pus blisters and later yellow crusts. Other possible symptoms include fever or swelling of the lymph nodes.

Other parts of the body can also become infected via the hands (through scratching). If bark lichen is treated correctly, it usually heals without complications or scars. The disease occurs most frequently in the warm months of spring and summer. Neurodermatitis and other skin diseases as well as disorders of the body's own defenses (immune deficiency) can promote infection.

Complications caused by inflammation of other organs (eyes, ears or kidneys) are very rare and can be prevented by timely treatment with ointments and/or antibiotics.

The incubation period is the time between infection with the pathogen and the onset of the disease. In the case of bark lichen, it is usually between two and ten days.

The cause of the skin disease is bacteria, usually staphylococci and streptococci. Transmission occurs as a so-called smear infection, i.e. via direct contact with the reddened areas of skin. However, the bacteria can also be transmitted via clothing and other laundry that has been in contact with it.

Hygienic measures must also be observed to prevent further spread of the smear infection. For example, fingernails should be cut short and kept clean.