Small blisters on the back

Introduction Small blisters on the back are caused by tinea versicolor, which occurs in sweaty areas such as the chest, abdomen, upper arms, back and neck, and sometimes on the face. The rash begins with tiny spots, mostly around the mouth of the hair follicle, and then gradually enlarges to form patches of varying sizes ranging from pale to dark brown, with small squama-like scales visible on it. Skin lesions develop with the prolongation of time, and spots of pigment loss can be formed over a long period of time, and it is not easy to subside. Pityriasis versicolor usually has few inflammatory reactions because the fungus only parasitizes the stratum corneum of the skin. When the skin lesions are active, occasionally there may be itching.

Cause

It is caused by a fungus, Pityrosporum. This kind of bacteria is a common saprophytic parasite on normal human skin, and it can only cause illness in some special cases. It is called sweat stains and can be seen to be related to sweating. Because of the formation of dirt and rot by sweat and dust and dander, it provides conditions for growth and reproduction of P. variabilis, so it is more common in tropical and subtropical regions. Young people, especially young men, sweat more because of their activities. If you don't change clothes and dry your skin in time, it is easy to cause tinea. It is also more common in people who use corticosteroids because of the prolonged period of epidermal cell replacement, which is conducive to fungal growth. If the hormone is stopped, the tinea versicolor will improve. In addition, physical weakness, malnutrition, diabetes and pregnancy can induce this disease.

an examination

Related inspection

Fungal examination blood routine

The tinea versicolor mainly occurs in the trunk, especially in the sweaty area. Sometimes the rash is darker in color and irregular in shape, much like the dirt on the skin. But the dirt can be washed away with hot water and soap, and the damage of the tinea versicolor is a pigment change, so it can't be washed off. If you have a plaque for a long time, leave some pale white patches on your skin that are easily confused with vitiligo. The pigment in the skin lesions of vitiligo is completely lost, and it is milky white. The hair growth on it is also white, and its boundary is clear, and the pigment of the edge skin increases. Generally, there is no scaling and itching, and there is no case of aggravation after excessive sweating. In addition to careful medical history and observation of skin lesion characteristics, fungal examination or scraping of scaly lesions under the microscope can be performed. Directly search for P. variabilis, or observe the skin lesions by filtering through UV light. If the pathogen is found under the microscope or yellow fluorescence is seen at the skin lesion, the diagnosis can be confirmed.

Differential diagnosis

The disease needs to be differentiated from vitiligo. The latter is mainly white in pigmentation and white in color. The edges of the skin may be pigmented. Generally, there is no desquamation, no itching, and no excessive sweating. Should also pay attention to the identification of anemia, rose pityriasis, red mites and so on.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.