Psoriasis, a genetic disease… but what it is exactly?

Psoriasis is not a simple skin rash but a disease that can be painful and debilitating, and affects the development of everyday activities.

It is originated in the malfunction of the immune system that causes an overproduction of skin cells –those responsible for replenishing the skin layers in constant renewal.

This excess reaches a level of substitution up to seven times higher than normal, causing the disease’s characteristic plaques that take the form of marked red spots covered with flaking. Furthermore, excessive cell production also produces the infiltration of white blood cells –T cells– into the skin.

The injuries are usually located on the trunk, elbows, knees, scalp and groins.


Although the specific origin of the disease is unknown, it is clear that it is a genetic disease –in fact, the gene whose alteration influences the appearance of the pathology has been located.

It is also known that it is a hereditary disease. If one of the two parents suffer from psoriasis, one out of eight children can show the disease. If both parents are affected, the probability rises to one out of four. However, being a psoriatic does not directly mean that the children will also suffer the disease.

It can also happen that the genetic alteration is inherited but the disease is not developed since exogenous –external– factors are also involved in its appearance.

Among the exogenous factors, we find:

– Chronic infections
– Nervous Stress
– Obesity
– Alcohol
– Diseases such as rheumatoid arthritis
– Hormonal changes
– Traumas (wounds, bruises, sunburn...)

Symptoms of Psoriasis

Psoriasis usually begins with one or more small patches becoming very scaly. It is possible that small swellings may appear around the affected area. Although the first patches can disappear by themselves, right after that others can easily be created. Some patches may always keep the size of the small finger nail, but others can grow and cover large areas of the body adopting a ring or spiral form.

Psoriasis normally affects the scalp, elbows, knees, back and buttocks. Flaking can be confused with severe dandruff, but the characteristic patches of psoriasis that mix scaly areas with others completely normal make the distinction between psoriasis and dandruff. Psoriasis can also appear around and under the nails –which thicken and become deformed. Eyebrows, armpits, navel and groins could also be affected.

In general, psoriasis only produces skin flaking. Itching is not very common either. When the areas covered with scales heal, the skin takes on a completely normal appearance and hair growth is restored. Most people with psoriasis have minimal discomfort –besides of the flaking– although the skin appearance can be unsightly.

Types of Psoriasis

There are many types of psoriasis, although experts prefer to speak of different forms of presentation of the disease. It can be classified per severity, shape and pattern of the scales.

Per severity
Mild psoriasis
Moderate psoriasis
Severe psoriasis

Per shape and pattern of the scales
Plaque psoriasis
Guttate psoriasis
Inverse psoriasis (in folds)
Erythrodermic psoriasis
Generalized pustular psoriasis
Nail psoriasis
Localized pustular psoriasis
Systemic arthritis
Arthritis mutilans


In the beginning the diagnosis can be uncertain since many other diseases can present similar patches and flaking. As the psoriasis advances, doctors can easily recognize its characteristic pattern of flaking, and therefore –in general– diagnostic tests are not needed. However, the doctor can proceed with a skin biopsy –removing a skin sample for examination using a microscope– to confirm the diagnosis.